Pap test

Definition

The Pap test (Pap smear) is the microscopic examination of cells scraped from the both the outer cervix (ectocervix) and the cervical canal (endocervix). It is called the "Pap" test after its developer, Dr. George N. Papanicolaou, who described a procedure for staining vaginal and cervical cells that gives clearly defined detail to the nuclear chromatin. Using the Papanicolaou stain, he developed a classification system for abnormal cervical cells. Before the application of the Pap test in the 1940s, cervical cancer caused approximately 26,000 deaths in the United States each year. The death rate from cervical cancer since the use of the Pap test has become widely accepted has been reduced by 70%.

Purpose

The Pap test is a screening test used to detect abnormal growth of cervical cells at an early stage, so that if necessary, treatment can be started before the cells become cancerous and invasive. The test helps physicians identify women who are at increased risk of cervical dysplasia (abnormal cells) or cervical cancer. Only an examination of the cervix, and samples of cervical tissue (biopsies) can diagnose precancerous and cancerous changes in the cells that line the uterus, called squamous epithelium.

This microscopic analysis of cells can detect cervical cancer, precancerous changes, inflammation (called vaginitis), infections, and some sexually transmitted diseases (STDs). The Pap test can sometimes detect endometrial (uterine) cancer or ovarian cancer, although it was not designed for this purpose.

Women should begin to have Pap tests at the age of 18 years or whenever they start having sex. Young people are more likely to have multiple sex partners, which increases their risk of certain diseases that can cause cancer, such as human papillomavirus (HPV). The American Cancer Society recommends that a Pap test be done annually for two consecutive negative examinations, then repeated once every three years until age 65 for women without symptoms of gynecologic problems. Many other doctors, however, recommend annual Pap tests for all their patients.

Women with certain risk factors should always have yearly tests. Those at highest risk for cervical cancer are women who started having sex before age 18; those with many sex partners (especially if they did not use condoms, which protect against STDs); those who have had STDs such as genital herpes or genital warts; and those who smoke. Women older than 40 also should have the test yearly, especially in the event of bleeding after menopause . Women over age 60 account for 25% of new cases of cervical cancer and 40% of deaths from this disease. Women who have had a hysterectomy (removal of the uterus) may need to have Pap tests, if the surgery was for cancer, or if the cervix was left in place. Pregnant women should have a Pap test as part of their first prenatal examination.

Women who have a positive test result should be retested more frequently. If atypical squamous cells or low-grade lesions are found they should be tested every four to six months until they have three consecutive normal results. The test should be repeated within two to three months if severe inflammation, infection , or post-menoposal atrophy is found. If atypical cells or low-grade lesions persist, or high-grade lesions are found, colposcopy (examination of the cervix with a magnifying lens) should be performed, and treatment initiated as indicated.

Precautions

The Pap smear is a microscopic evaluation of individual cells, a process that requires interpretation. Differentiation of inflammatory, reactive, and atrophied cells from atypical cells is difficult and cannot always be performed with complete certainty. The test is not 100% sensitive and between 5–10% of cervical abnormalities may be missed. Most false negatives result from poor sample collection (insufficient cervical cells) or poor smear preparation. The finding of abnormal cells on a Pap smear does not mean that the cells were present on previous exams.

The Pap test should be performed in the middle of the menstrual cycle to prevent interference from blood . Sexual intercourse, douching, or the use of vaginal suppositories may affect results. Other factors that can affect test results include: water or lubricant on the specimen from the speculum; blood, mucus, or pus on the slide that obstructs the view of epithelial cells; cell damage during collection; and improper slide fixation. An acceptable smear is one that is correctly labeled with the patient's name, age, and last menstrual period; contains squamous cells covering at least 10% of the slide; and demonstrates the presence of cells from the endocervix and transformation zone. The transformation zone is the area where the squamous epithelium of the ectocervix meets the glandular epithelium of the endocervix.

Description

The Pap test is an extremely cost-effective and beneficial test able to detect about 95% of cervical cancer. According to a report published May 16, 2000 in the Annals of Internal Medicine, the widespread use of this diagnostic procedure decreased the number of cervical cancers in the United Sates from 14.2 per 100,000 in 1973, to 7.8 per 100,000 in 1994. However, the disease still ranks as the ninth-leading cause of cancer deaths in U.S. women.

During the pelvic examination, an instrument called a speculum is inserted into the vagina to open it. A spatula, (Ayre spatula) that is flat at one end and curved at the other so that its contour complements the ectocervix is used to collect the sample. The spatula is firmly rotated using a circular motion to scrape the cells off the ecto-cervix. The flat end can be used to pick up cells which have exfoliated from the rear of the vagina. This procedure, called vaginal pool sampling, is recommended for women in menopause and if signs of inflammation are seen. A tiny brush, pointed spatula, or cotton-tipped swab is used to collect cells from the endocervix. These samples can be mixed and spread evenly on a single glass slide, or a slide or slide section can be used for each. The slide should be dipped in 95% alcohol or sprayed with fixative immediately. Though some women find the procedure uncomfortable, it is usually painless and only takes five to 10 minutes.

A new technique called the Thin Prep is being used by some physicians because it is purported to reduce the false negative rate caused by inadequate smear preparation. For the Thin Prep, the sample is placed in a vial containing a preservative solution. The vial is labeled and sent to the laboratory where a processing instrument disrupts the blood cells and mucus and spreads the decontaminated sample in a thin layer over the slide. Unlike the classical procedure, cells are not left on the collection device. This results in a greater yield of epithelial cells to examine. The staining detail is easier to evaluate because the epithelial cells are not obscured by blood cells or mucus.

Smears are stained with the Papanicolaou stain when they reach the lab. The Pap stain begins with rehydrating the cells in water. The cells are stained with Gill hematoxylin, then dehydrated with 95% ethanol. They are stained with OG-6 followed by EA-65, then fully dehydrated with absolute ethanol. In the last step, they are cleared with xylol, and a coverglass is applied. The entire smear is examined under a microscope . In addition to detecting and classifying abnormalities within the squamous epithelium and glandular epithelium, the smears are also examined for the presence of inflammatory cells (polymorphonuclear white cells, lymphocytes, histiocytes), normal vaginal flora (Lactobacilli), coccobacilli (indicative of vaginal infection), trichomonads (vaginal parasites), yeast, and cytopathic effects of viruses in the epithelial cells.

Squamous epithelial cells from the cervix are evaluated for abnormal intracellular changes that indicate a risk of cancerous transformation. Two systems of classification are widely employed, the CIN (Richart) and Bethesda systems. Both describe a progression of cells from normal to low risk, then to high risk, then to malignant

cells. The CIN system uses the term, cervical intraepithelial neoplasia (CIN) to describe premalignant cells. CIN-I is characterized by mild cellular abnormalities (mild dysplasia), CIN-II moderate dysplasia, and CIN-III severe dysplasia. CIN-III includes the presence of immature cells with cancerous features that have not yet invaded the surrounding connective tissue. This is called carcinoma in situ. When such cells are found beyond the transformation zone (within the underlying stroma), the lesion is classified as invasive cancer (squamous carcinoma). The CIN classification system classifies cells that are most likely benign (called squamous atypica) and low-risk precancerous cells in the category of CIN-I. In 1989, the Bethesda system was introduced in order to more clearly define the difference between mild dysplasia that is likely to be benign and that which is pre-cancerous. The former comprise a group called ASCUS which stands for atypical squamous cells of undetermined significance. This distinguishes cells that are often reactive from those of the next group, low-grade intraepithelial neoplasia (LSIL) that show precancerous changes, but are at a low risk of transforming into cancerous cells. ASCUS is reserved for cells that cannot be conclusively called benign. Classification of a smear as ASCUS is based upon judgement and depends upon the quality of the smear and the numbers and appearance of atypical cells present. A pap test in which ASCUS is found should be repeated in three to four months, and if ASCUS is detected the second time, the patient should be evaluated by colposcopy and biopsy. Between 19% and 57% of these patients will be reclassified as SIL on the

basis of biopsy. The LSIL category is the counterpart of the CIN-I category. The final category of the Bethesda system is high-grade intraepithelial neoplasia (HSIL) which comprises both CIN-II and CIN-III groups including carcinoma in situ. Beyond HSIL, the lesion is classified as an invasive squamous cell carcinoma.

In general, cervical cells are classified as ASCUS if the nuclear enlargement is no greater than three-fold the size of the nucleus of a normal intermediate squamous cell, or there is mild hyperchromasia (increased chromatin staining). LSIL cells are superficial or intermediate squamous cells that display a nucleus that is at least three-fold larger than the normal intermediate squamous cell. There is moderate variation in the size and shape of the nucleus. Nuclear hyperchromasia is present either as uniformly granular or smudged chromatin staining. In addition, cells that are associated with infection by HPV have a cytoplasm with hollowed-out cavities. About 80% of cervical cancers are associated with HPV infection. Therefore, these cells, called koilocytes, are classified as LSIL provided that some nuclear abnormality or binucleation is present. HSIL cells are immature squamous cells (smaller cells) with a three-fold or greater nuclear enlargement, an increased nuclear to cytoplasm ratio, severe hyperchromasia with irregular chromatin and nuclear membrane contour. They are usually seen in streaming rows or groups of attached cells.

Preparation

While most women are not routinely advised to make any special preparations for a Pap test, some simple preparations may help to ensure that the results are reliable. Among the measures that may help increase test reliability are:

• abstaining from sexual intercourse 24 hours prior to the test
• not douching 18–72 hours before the test
• avoiding vaginal creams or medications one week before the test

If possible, women may want to ensure that their test is performed by an experienced gynecologist and sent to a certified laboratory. Certification requires successful participation in a proficiency testing program approved by the U.S. Department of Health and Human Services. In such a program every cytotechnologist reading pap smears is tested at least once per year and is required to meet specific performance criteria.

Before the exam, the physician will take a complete sexual history to determine a woman's risk status for cervical cancer. Questions may include date and results of the last Pap test, any history of abnormal Pap tests, date of last menstrual period and any irregularity, use of hormones and birth control, family history of gynecologic disorders, and any vaginal symptoms. These topics are relevant to the interpretation of the Pap test, especially if any abnormalities are detected. Immediately before the Pap test, the woman should empty her bladder to avoid discomfort during the procedure.

Aftercare

Harmless cervical bleeding is possible immediately after the test; women may need to use a sanitary napkin. They should also be sure to comply with their doctor's orders for follow-up visits.

Complications

No appreciable health risks are associated with the Pap test. However, abnormal results (whether valid or due to technical error) can cause significant anxiety . Women may wish to have their sample retested, either by the same laboratory or via computer-assisted screening. Two re-screening programs approved by the Food and Drug Administration are called Papnet and AutoPap QC.

Results

Normal (negative) results from the laboratory exam mean that no atypical cells were detected, and the cervix is normal. It is important to remember that an abnormal (positive) result does not necessarily indicate cancer. Fully 60–70% of abnormal results resolve by themselves, and only 1% of mild abnormalities ever develop into cancer. Between 19% and 57% of patients with ASCUS will be reclassified as having SIL (mostly LSIL) following biopsy. Approximately 57% of LSIL lesions regress on their own (i.e., return to normal); 32% remain LSIL on retesting, 11% progress to HSIL, and 1% may progress to invasive carcinoma. Approximately 43% of HSIL (CINII) lesions regress, 35% remain HSIL on retesting, and 22% progress to CIN-III. Approximately 5% of HSIL (CIN-II) lesions progress to invasive cancer. Approximately 32% of HSIL (CIN-III) lesions regress, up to 55% persist on repeat exam, and more than 12% progress to invasive carcinoma.

Treatment

CHANGES OF UNKNOWN CAUSE (ASCUS OR SQUAMOUS ATYPICA). The most common abnormality (found in 50–60% of abnormal tests) is ASCUS. If squamous atypica is thought to be inflammatory or reactive, this will be noted on the report as well as any evidence of infection (e.g., coccobacilli, yeast, white blood cells) seen on the microscopic exam. These women may be treated for infection and then undergo repeat Pap testing in two to three months. If ASCUS is present without signs of inflammation, re-testing is performed every four to six months for two years or until three consecutive tests are negative. If the lesion persists, or ASCUS is seen twice within a two-year period, colposcopy is recommended.

DYSPLASIA. Typically, dysplasia causes no symptoms, although women may experience abnormal vaginal bleeding. Because dysplasia can be precancerous, it should be treated if it is moderate or severe. Treatment of dysplasia depends on the degree of abnormality. In women with no other risk factors for cervical cancer, mild dysplasia may be simply observed over time with repeat testing, every four to six months as described above. If the lesion persists, colposcopy with biopsy and scraping of the endocervix are often recommended.

The second most common finding (about 30–40% of abnormal tests) is LSIL, which includes mild dysplasia or CIN I and changes caused by HPV. Unlike cancer cells, these cells do not invade normal tissues. Women are most susceptible to mild dysplasia at ages 25–35 years. HSIL (found in 5–10% of abnormal Pap tests) includes moderate to severe dysplasia or carcinoma in situ (CIN II orIII). The frequency of HSIL is highest at ages 30–40. In women with HSIL lesions, colposcopy, biopsy, and treatment (excision or destruction of the lesion) are performed. In addition to surgical resection (removal), several outpatient techniques are available: conization (removal of a cone-shaped piece of tissue), laser surgery , cryotherapy (freezing), electrosurgical cauterization, and radiation. Cure rates are nearly 100% after prompt and appropriate treatment of carcinoma in situ. Of course, frequent checkups are then necessary.

KEY TERMS

Carcinoma in situ —Precancerous cells that are present only in the ectocervix (i.e., do not extend beyond the basement membrane). The abnormal cells do not extend beyond the transformation zone.

Cervical intraepithelial neoplasia (CIN) —A term used to categorize degrees of dysplasia arising in the cervical epithelium (outer cervix).

Cervix —The opening between the vagina and the uterus, or womb.

Cytology —The study of cells, their origin, structure, function, and pathology.

Dysplasia —Abnormal changes in cells.

Human papilloma virus (HPV) —The leading STD in the United States. Various types of HPV are known to cause cancer.

Neoplasia —Abnormal growth of cells, which may lead to a neoplasm, or tumor.

Squamous intraepithelial lesion (SIL) —A term used to categorize the severity of abnormal changes arising in the squamous cells of the cerrvix.

In addition to abnormal squamous epithelium, abnormal glandular cells from the endocervix may be found. Atypical glandular cells of undetermined significance (AGUS) is used to designate cells that cannot be classified with certainty as benign, precancerous, or cancerous. AGUS should be investigated further to determine the risk of endometrial carcinoma. Malignant glandular cells may also be found on the Pap smear and may result from cervical or vaginal adenocarcinoma. This cancer is uncommon in women under 40, and most common in women over 50 who have postmenopausal bleeding. Malignant glandular cells are more often recovered from vaginal pool sampling or aspiration than from cervical scraping, and therefore, vaginal cell smears should be made along with cervical smears for women in menopause. Hysterectomy is recommended for confirmed cases of endometrial adenocarcinoma.

CANCER. Human papilloma virus (HPV), the most common STD in the United States, may be responsible for many cervical cancers. Cancer may be manifested by unusual vaginal bleeding or discharge, bowel and bladder problems, and pain . The peak ages for cervical cancer are between 45 and 55 years. Biopsy is indicated when any abnormal growth is found on the cervix, even if the Pap test is negative.

Invasive cervical cancer is usually treated with surgery or radiation, or both. Most cases of invasive cervical cancer are treated with radical hysterectomy. Chemotherapy may be used if the cancer has spread to lymph nodes or other organs. Survival rates at five years after treatment of early invasive cancer are about 90%; rates are below 60% for more severe invasive cancer. That is why prevention, risk reduction, and frequent Pap tests are the best defense for a woman's gynecologic health.

Health care team roles

The slides are prepared by a gynecologist. Cytotechnologists, laboratory professionals who specialize in the study of cells, read the Pap smears looking for abnormal cells. Abnormal findings may be reviewed by the laboratory's pathologist.

Resources

BOOKS

Berek, Jonathan S., Eli Y. Adashi, and Paula A. Hillard. Novak's Gynecology. 12th ed. Baltimore: Williams & Wilkins, 1996.

Chernecky, Cynthia C., and Berger, Barbara J. Laboratory Tests and Diagnostic Procedures. 3rd ed. Philadelphia: W. B. Saunders Company, 2001.

Illustrated Guide to Diagnostic Tests. 2nd ed. Springhouse, PA: Springhouse Corporation, 1998.

Kee, Joyce LeFever. Handbook of Laboratory and Diagnostic Tests. 4th ed. Upper Saddle River, NJ: Prentice Hall, 2001.

Slupik, Ramona I., ed. American Medical Association Complete Guide to Women's Health. New York: Random House, 1996.

PERIODICALS

MacLennan, Anne. "Pap Test Flawed But Only Proven Curb On Cervical Cancer." Annals of Internal Medicine 132 (May 16, 2000): 810-819.

ORGANIZATIONS

American College of Obstetricians and Gynecologists. 409 12th St. SW, PO Box 96920, Washington, DC 20090-6920. (202) 638-5577. <http://www.acog.com>.

National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services. 9000 Rockville Pike, Bethesda, MD 20892. (301) 496-0265. <http://cancernet.nci.nih.gov/>.

Victoria E. DeMoranville

Pap Test

Definition

The Pap test (Pap smear) is the microscopic examination of cells scraped from the both the outer cervix (ectocervix) and the cervical canal (endocervix). It is called the "Pap" test after its developer, Dr. George N. Papanicolaou, who described a procedure for staining vaginal and cervical cells that gives clearly defined detail to the nuclear chromatin. Using the Papanicolaou stain, he developed a classification system for abnormal cervical cells. Before the application of the Pap test in the 1940s, cervical cancer caused approximately 26,000 deaths in the United States each year. The death rate from cervical cancer since the use of the Pap test has become widely accepted has been reduced by 70%.

Purpose

The Pap test is a screening test used to detect abnormal growth of cervical cells at an early stage, so that if necessary, treatment can be started before the cells become cancerous and invasive. The test helps physicians identify women who are at increased risk of cervical dysplasia (abnormal cells) or cervical cancer. Only an examination of the cervix, and samples of cervical tissue (biopsies) can diagnose precancerous and cancerous changes in the cells that line the uterus, called squamous epithelium.

This microscopic analysis of cells can detect cervical cancer, precancerous changes, inflammation (called vaginitis), infections, and some sexually transmitted diseases (STDs). The Pap test can sometimes detect endometrial (uterine) cancer or ovarian cancer, although it was not designed for this purpose.

Women should begin to have Pap tests at the age of 18 years or whenever they start having sex. Young people are more likely to have multiple sex partners, which increases their risk of certain diseases that can cause cancer, such as human papillomavirus (HPV). The American Cancer Society recommends that a Pap test be done annually for two consecutive negative examinations, then repeated once every three years until age 65 for women without symptoms of gynecologic problems. Many other doctors, however, recommend annual Pap tests for all their patients.

Women with certain risk factors should always have yearly tests. Those at highest risk for cervical cancer are women who started having sex before age 18; those with many sex partners (especially if they did not use condoms, which protect against STDs); those who have had STDs such as genital herpes or genital warts; and those who smoke. Women older than 40 also should have the test yearly, especially in the event of bleeding after menopause. Women over age 60 account for 25% of new cases of cervical cancer and 40% of deaths from this disease. Women who have had a hysterectomy (removal of the uterus) may need to have Pap tests, if the surgery was for cancer, or if the cervix was left in place. Pregnant women should have a Pap test as part of their first prenatal examination.

Women who have a positive test result should be retested more frequently. If atypical squamous cells or low-grade lesions are found they should be tested every four to six months until they have three consecutive normal results. The test should be repeated within two to three months if severe inflammation, infection, or postmenoposal atrophy is found. If atypical cells or low-grade lesions persist, or high-grade lesions are found, colposcopy (examination of the cervix with a magnifying lens) should be performed, and treatment initiated as indicated.

Precautions

The Pap smear is a microscopic evaluation of individual cells, a process that requires interpretation. Differentiation of inflammatory, reactive, and atrophied cells from atypical cells is difficult and cannot always be performed with complete certainty. The test is not 100% sensitive and between 5-10% of cervical abnormalities may be missed. Most false negatives result from poor sample collection (insufficient cervical cells) or poor smear preparation. The finding of abnormal cells on a Pap smear does not mean that the cells were present on previous exams.

The Pap test should be performed in the middle of the menstrual cycle to prevent interference from blood. Sexual intercourse, douching, or the use of vaginal suppositories may affect results. Other factors that can affect test results include: water or lubricant on the specimen from the speculum; blood, mucus, or pus on the slide that obstructs the view of epithelial cells; cell damage during collection; and improper slide fixation. An acceptable smear is one that is correctly labeled with the patient's name, age, and last menstrual period; contains squamous cells covering at least 10% of the slide; and demonstrates the presence of cells from the endocervix and transformation zone. The transformation zone is the area where the squamous epithelium of the ectocervix meets the glandular epithelium of the endocervix.

Description

The Pap test is an extremely cost-effective and beneficial test able to detect about 95% of cervical cancer. According to a report published May 16, 2000 in the Annals of Internal Medicine, the widespread use of this diagnostic procedure decreased the number of cervical cancers in the United Sates from 14.2 per 100,000 in 1973, to 7.8 per 100,000 in 1994. However, the disease still ranks as the ninth-leading cause of cancer deaths in U.S. women.

During the pelvic examination, an instrument called a speculum is inserted into the vagina to open it. A spatula, (Ayre spatula) that is flat at one end and curved at the other so that its contour complements the ectocervix is used to collect the sample. The spatula is firmly rotated using a circular motion to scrape the cells off the ectocervix. The flat end can be used to pick up cells which have exfoliated from the rear of the vagina. This procedure, called vaginal pool sampling, is recommended for women in menopause and if signs of inflammation are seen. A tiny brush, pointed spatula, or cotton-tipped swab is used to collect cells from the endocervix. These samples can be mixed and spread evenly on a single glass slide, or a slide or slide section can be used for each. The slide should be dipped in 95% alcohol or sprayed with fixative immediately. Though some women find the procedure uncomfortable, it is usually painless and only takes five to 10 minutes.

A new technique called the Thin Prep is being used by some physicians because it is purported to reduce the false negative rate caused by inadequate smear preparation. For the Thin Prep, the sample is placed in a vial containing a preservative solution. The vial is labeled and sent to the laboratory where a processing instrument disrupts the blood cells and mucus and spreads the decontaminated sample in a thin layer over the slide. Unlike the classical procedure, cells are not left on the collection device. This results in a greater yield of epithelial cells to examine. The staining detail is easier to evaluate because the epithelial cells are not obscured by blood cells or mucus.

Smears are stained with the Papanicolaou stain when they reach the lab. The Pap stain begins with rehydrating the cells in water. The cells are stained with Gill hematoxylin, then dehydrated with 95% ethanol. They are stained with OG-6 followed by EA-65, then fully dehydrated with absolute ethanol. In the last step, they are cleared with xylol, and a coverglass is applied. The entire smear is examined under a microscope. In addition to detecting and classifying abnormalities within the squamous epithelium and glandular epithelium, the smears are also examined for the presence of inflammatory cells (polymor-phonuclear white cells, lymphocytes, histiocytes), normal vaginal flora (Lactobacilli), coccobacilli (indicative of vaginal infection), trichomonads (vaginal parasites), yeast, and cytopathic effects of viruses in the epithelial cells.

Squamous epithelial cells from the cervix are evaluated for abnormal intracellular changes that indicate a risk of cancerous transformation. Two systems of classification are widely employed, the CIN (Richart) and Bethesda systems. Both describe a progression of cells from normal to low risk, then to high risk, then to malignant cells. The CIN system uses the term, cervical intraepithelial neoplasia (CIN) to describe premalignant cells. CIN-I is characterized by mild cellular abnormalities (mild dysplasia), CIN-II moderate dysplasia, and CIN-III severe dysplasia. CIN-III includes the presence of immature cells with cancerous features that have not yet invaded the surrounding connective tissue. This is called carcinoma in situ. When such cells are found beyond the transformation zone (within the underlying stroma), the lesion is classified as invasive cancer (squamous carcinoma). The CIN classification system classifies cells that are most likely benign (called squamous atypica) and low-risk precancerous cells in the category of CIN-I. In 1989, the Bethesda system was introduced in order to more clearly define the difference between mild dysplasia that is likely to be benign and that which is precancerous. The former comprise a group called ASCUS which stands for atypical squamous cells of undetermined significance. This distinguishes cells that are often reactive from those of the next group, low-grade intraepithelial neoplasia (LSIL) that show precancerous changes, but are at a low risk of transforming into cancerous cells. ASCUS is reserved for cells that cannot be conclusively called benign. Classification of a smear as ASCUS is based upon judgement and depends upon the quality of the smear and the numbers and appearance of atypical cells present. A pap test in which ASCUS is found should be repeated in three to four months, and if ASCUS is detected the second time, the patient should be evaluated by colposcopy and biopsy. Between 19% and 57% of these patients will be reclassified as SIL on the basis of biopsy. The LSIL category is the counterpart of the CIN-I category. The final category of the Bethesda system is high-grade intraepithelial neoplasia (HSIL) which comprises both CINII and CIN-III groups including carcinoma in situ. Beyond HSIL, the lesion is classified as an invasive squamous cell carcinoma.

In general, cervical cells are classified as ASCUS if the nuclear enlargement is no greater than three-fold the size of the nucleus of a normal intermediate squamous cell, or there is mild hyperchromasia (increased chromatin staining). LSIL cells are superficial or intermediate squamous cells that display a nucleus that is at least three-fold larger than the normal intermediate squamous cell. There is moderate variation in the size and shape of the nucleus. Nuclear hyperchromasia is present either as uniformly granular or smudged chromatin staining. In addition, cells that are associated with infection by HPV have a cytoplasm with hollowed-out cavities. About 80% of cervical cancers are associated with HPV infection. Therefore, these cells, called koilocytes, are classified as LSIL provided that some nuclear abnormality or binucleation is present. HSIL cells are immature squamous cells (smaller cells) with a three-fold or greater nuclear enlargement, an increased nuclear to cytoplasm ratio, severe hyperchromasia with irregular chromatin and nuclear membrane contour. They are usually seen in streaming rows or groups of attached cells.

Preparation

While most women are not routinely advised to make any special preparations for a Pap test, some simple preparations may help to ensure that the results are reliable. Among the measures that may help increase test reliability are:

• Abstain from sexual intercourse 24 hours prior to the test.
• Do not douch 18-72 hours before the test.
• Avoid vaginal creams or medications one week before the test.

If possible, women may want to ensure that their test is performed by an experienced gynecologist and sent to a certified laboratory. Certification requires successful participation in a proficiency testing program approved by the U.S. Department of Health and Human Services. In such a program every cytotechnologist reading pap smears is tested at least once per year and is required to meet specific performance criteria.

Before the exam, the physician will take a complete sexual history to determine a woman's risk status for cervical cancer. Questions may include date and results of the last Pap test, any history of abnormal Pap tests, date of last menstrual period and any irregularity, use of hormones and birth control, family history of gynecologic disorders, and any vaginal symptoms. These topics are relevant to the interpretation of the Pap test, especially if any abnormalities are detected. Immediately before the Pap test, the woman should empty her bladder to avoid discomfort during the procedure.

Aftercare

Harmless cervical bleeding is possible immediately after the test; women may need to use a sanitary napkin. They should also be sure to comply with their doctor's orders for follow-up visits.

Complications

No appreciable health risks are associated with the Pap test. However, abnormal results (whether valid or due to technical error) can cause significant anxiety. Women may wish to have their sample retested, either by the same laboratory or via computer-assisted screening. Two re-screening programs approved by the Food and Drug Administration are called Papnet and AutoPap QC.

Results

Normal (negative) results from the laboratory exam mean that no atypical cells were detected, and the cervix is normal. It is important to remember that an abnormal (positive) result does not necessarily indicate cancer. Fully 60-70% of abnormal results resolve by themselves, and only 1% of mild abnormalities ever develop into cancer. Between 19% and 57% of patients with ASCUS will be reclassified as having SIL (mostly LSIL) following biopsy. Approximately 57% of LSIL lesions regress on their own (i.e., return to normal); 32% remain LSIL on retesting, 11% progress to HSIL, and 1% may progress to invasive carcinoma. Approximately 43% of HSIL (CIN-II) lesions regress, 35% remain HSIL on retesting, and 22% progress to CIN-III. Approximately 5% of HSIL (CIN-II) lesions progress to invasive cancer. Approximately 32% of HSIL (CIN-III) lesions regress, up to 55% persist on repeat exam, and more than 12% progress to invasive carcinoma.

Treatment

CHANGES OF UNKNOWN CAUSE (ASCUS OR SQUAMOUS ATYPICA). The most common abnormality (found in 50-60% of abnormal tests) is ASCUS. If squamous atypica is thought to be inflammatory or reactive, this will be noted on the report as well as any evidence of infection (e.g., coccobacilli, yeast, white blood cells) seen on the microscopic exam. These women may be treated for infection and then undergo repeat Pap testing in two to three months. If ASCUS is present without signs of inflammation, re-testing is performed every four to six months for two years or until three consecutive tests are negative. If the lesion persists, or ASCUS is seen twice within a two-year period, colposcopy is recommended.

DYSPLASIA. Typically, dysplasia causes no symptoms, although women may experience abnormal vaginal bleeding. Because dysplasia can be precancerous, it should be treated if it is moderate or severe. Treatment of dysplasia depends on the degree of abnormality. In women with no other risk factors for cervical cancer, mild dysplasia may be simply observed over time with repeat testing, every four to six months as described above. If the lesion persists, colposcopy with biopsy and scraping of the endocervix are often recommended.

The second most common finding (about 30-40% of abnormal tests) is LSIL, which includes mild dysplasia or CIN I and changes caused by HPV. Unlike cancer cells, these cells do not invade normal tissues. Women are most susceptible to mild dysplasia at ages 25-35 years. HSIL (found in 5-10% of abnormal Pap tests) includes moderate to severe dysplasia or carcinoma in situ (CIN II or III). The frequency of HSIL is highest at ages 30-40. In women with HSIL lesions, colposcopy, biopsy, and treatment (excision or destruction of the lesion) are performed. In addition to surgical resection (removal), several outpatient techniques are available: conization (removal of a cone-shaped piece of tissue), laser surgery, cryotherapy (freezing), electrosurgical cauterization, and radiation. Cure rates are nearly 100% after prompt and appropriate treatment of carcinoma in situ. Of course, frequent checkups are then necessary.

In addition to abnormal squamous epithelium, abnormal glandular cells from the endocervix may be found. Atypical glandular cells of undetermined significance (AGUS) is used to designate cells that cannot be classified with certainty as benign, precancerous, or cancerous. AGUS should be investigated further to determine the risk of endometrial carcinoma. Malignant glandular cells may also be found on the Pap smear and may result from cervical or vaginal adenocarcinoma. This cancer is uncommon in women under 40, and most common in women over 50 who have postmenopausal bleeding. Malignant glandular cells are more often recovered from vaginal pool sampling or aspiration than from cervical scraping, and therefore, vaginal cell smears should be made along with cervical smears for women in menopause. Hysterectomy is recommended for confirmed cases of endometrial adenocarcinoma.

CANCER. Human papilloma virus (HPV), the most common STD in the United States, may be responsible for many cervical cancers. Cancer may be manifested by unusual vaginal bleeding or discharge, bowel and bladder problems, and pain. The peak ages for cervical cancer are between 45 and 55 years. Biopsy is indicated when any abnormal growth is found on the cervix, even if the Pap test is negative.

Invasive cervical cancer is usually treated with surgery or radiation, or both. Most cases of invasive cervical cancer are treated with radical hysterectomy. Chemotherapy may be used if the cancer has spread to lymph nodes or other organs. Survival rates at five years after treatment of early invasive cancer are about 90%; rates are below 60% for more severe invasive cancer. That is why prevention, risk reduction, and frequent Pap tests are the best defense for a woman's gynecologic health.

Health care team roles

The slides are prepared by a gynecologist. Cytotechnologists, laboratory professionals who specialize in the study of cells, read the Pap smears looking for abnormal cells. Abnormal findings may be reviewed by the laboratory's pathologist.

KEY TERMS

Carcinoma in situ— Precancerous cells that are present only in the ectocervix(i.e., do not extend beyond the basement membrane). The abnormal cells do not extend beyond the transformation zone.

Cervical intraepithelial neoplasia (CIN)— A term used to categorize degrees of dysplasia arising in the cervical epithelium (outer cervix).

Cervix— The opening between the vagina and the uterus, or womb.

Cytology— The study of cells, their origin, structure, function and pathology.

Dysplasia— Abnormal changes in cells.

Human papilloma virus (HPV)— The leading STD in the United States. Various types of HPV are known to cause cancer.

Neoplasia— Abnormal growth of cells, which may lead to a neoplasm, or tumor.

Squamous intraepithelial lesion (SIL)— A term used to categorize the severity of abnormal changes arising in the squamous cells of the cerrvix.

Resources

BOOKS

Berek, Jonathan S., Eli Y. Adashi, and Paula A. Hillard. Novak's Gynecology. 12th ed. Baltimore: Williams & Wilkins, 1996.

Chernecky, Cynthia C, and Barbara J. Berger. Laboratory Tests and Diagnostic Procedures. 3rd ed. Philadelphia, PA: W. B. Saunders Company, 2001.

Illustrated Guide to Diagnostic Tests. 2nd ed. Springhouse, PA: Springhouse Corporation, 1998.

Kee, Joyce LeFever. Handbook of Laboratory and Diagnostic Tests. 4th ed. Upper Saddle River, NJ: Prentice Hall, 2001.

Slupik, Ramona I., ed. American Medical Association Complete Guide to Women's Health. New York: Random House, 1996.

PERIODICALS

MacLennan, Anne. "Pap Test Flawed But Only Proven Curb On Cervical Cancer." Annals of Internal Medicine 132 (May 16, 2000): 810-819.

ORGANIZATIONS

American College of Obstetricians and Gynecologists. 409 12th St. SW, PO Box 96920, Washington, DC 20090-6920. (202) 638-5577. 〈http://www.acog.com〉.

National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services. 9000 Rockville Pike, Bethesda, MD 20892. (301) 496-0265. 〈http://cancernet.nci.nih.gov/〉.

Pap Test

Definition

The Pap test is a procedure in which a physician scrapes cells from the cervix or vagina to check for cervical cancer, vaginal cancer, or abnormal changes that could lead to cancer. It often is called a "Pap smear."

Purpose

The Pap test is used to detect abnormal growth of cervical cells at an early stage so that treatment can be started when the condition is easiest to treat. This microscopic analysis of cells can detect cervical cancer, precancerous changes, inflammation (vaginitis), infections, and some sexually transmitted diseases (STDs). The Pap test can occasionally detect endometrial (uterine) cancer or ovarian cancer, although it was not designed for this purpose.

Women should begin to have Pap tests at the age of 21 or within three years of becoming sexually active, whichever comes first. Young people are more likely to have multiple sex partners, which increases their risk of certain diseases that can cause cancer, such as human papillomavirus (HPV).

The American Cancer Society (ACS) updated its guidelines concerning Pap test frequency in late 2002. In brief, women should continue screening every year with regular Pap tests until age 30, every two years if using the liquid-based Pap test. Once a woman age 30 and older has had three normal results in a row, she may get screened every two to three years. A doctor may suggest more frequent screening if a woman has certain risk factors for cervical cancer. Women who have had total hysterectomies including the removal of the cervix do not need Pap tests unless the hysterectomy resulted from cervical cancer. Those over age 70 who have had three normal results generally do not need to continue having Pap tests under the new guidelines.

Women with certain risk factors may have yearly tests. Those at highest risk for cervical cancer are women who started having sex before age 18, those with many sex partners (especially if they did not use condoms, which protect against STDs), those who have had STDs such as genital herpes or genital warts, and those who smoke. Women older than 40 may have the test yearly, if experiencing bleeding after menopause. Women who have had a positive test result in the past may need screening every six months. Women who have had cervical cancer or precancer should have regular Pap smears.

Other women also benefit from the Pap test. Women over age 65 account for 25% of all cases of cervical cancer and 41% of deaths from this disease. Women over age 65 who have never had a Pap smear benefit the most from the test. Some women have the cervix left in place after hysterectomy and will continue to receive regular Pap tests. Finally, a pregnant woman should have a Pap test as part of her first prenatal examination.

The Pap smear is a screening test. It identifies women who are at increased risk of cervical dysplasia (abnormal cells) or cervical cancer. Only an examination of the cervix with a special lighted instrument (colposcopy ) and samples of cervical tissue (biopsies) can actually diagnose these problems.

Precautions

The Pap test is usually not done during the menstrual period because of the presence of blood cells. The best time is in the middle of the menstrual cycle.

Description

The Pap test is an extremely cost-effective and beneficial exam. Cervical cancer used to be a leading cause of cancer deaths in American women, but widespread use of this diagnostic procedure reduced the death rate from this disease by 74% between 1955 and 1992. A 2003 study reported that the test reduces rates of invasive cervical cancer by as much as 94%. In 2003, the FDA approved a new screening test that combines DNA testing for the HPV type that causes the most cases of cervical cancer with the standard Pap test, increasing its screening value.

The Pap test, sometimes called a cervical smear, is the microscopic examination of cells scraped from both the outer cervix and the cervical canal. (The cervix is the opening between the vagina and the uterus, or womb.) It is called the "Pap" test after its developer, Dr. George N. Papanicolaou. This simple procedure is performed during a gynecologic examination and is usually covered by insurance. For those with coverage, Medicare will pay for one screening Pap smear every three years.

During the pelvic examination, an instrument called a speculum is inserted into the vagina to open it. The doctor then uses a tiny brush, or a cotton-tipped swab and a small spatula to wipe loose cells off the cervix and to scrape them from the inside of the cervix. The cells are transferred or "smeared" onto glass slides, the slides are treated to stabilize the cells, and the slides are sent to a laboratory for microscopic examination. The entire procedure is usually painless and takes five to 10 minutes at most.

The newer method called liquid-based cytology, or the liquid-based Pap test, involves spreading the cells more evenly on a slide after removing them from the sample. The liquid-based method prevents cells from drying out and becoming distorted. Studies show that liquid-based testing slightly improves cancer detection and greatly improves detection of precancers, but it costs more than the traditional Pap test. Trade names in 2003 for liquid-based Pap smears were ThinPrep and AutoCyte.

Preparation

The Pap test may show abnormal results when a woman is healthy or normal results in women with cervical abnormalities as much as 25% of the time. It may even miss up to 5% of cervical cancers. Some simple preparations may help to ensure that the results are reliable. Among the measures that may help increase test reliability are:

• avoiding sexual intercourse for two days before the test
• not using douches for two or three days before the test

• avoiding tampons, vaginal creams, or birth control foams or jellies for two to three days before the test
• scheduling the Pap smear when not menstruating.

However, most women are not routinely advised to make any special preparations for a Pap test.

If possible, women may want to ensure that their test is performed by an experienced gynecologist, physician, or provider and sent to a reputable laboratory. The physician should be confident in the accuracy of the chosen lab.

Before the exam, the physician will take a complete sexual history to determine a woman's risk status for cervical cancer. Questions may include date and results of the last Pap test, any history of abnormal Pap tests, date of last menstrual period and any irregularity, use of hormones and birth control, family history of gynecologic disorders, and any vaginal symptoms. These topics are relevant to the interpretation of the Pap test, especially if any abnormalities are detected. Immediately before the Pap test, the woman should empty her bladder to avoid discomfort during the procedure.

Aftercare

Harmless cervical bleeding is possible immediately after the test; a woman may need to use a sanitary napkin. She should also be sure to comply with her doctor's orders for follow-up visits.

Risks

No appreciable health risks are associated with the Pap test. However, abnormal results (whether valid or due to technical error) can cause significant anxiety. Women may wish to have their sample double-checked, either by the same laboratory or by the new technique of computer-assisted rescreening. The Food and Drug Administration (FDA) has approved the use of AutoPap and PAPNET to doublecheck samples that have been examined by technologists. AutoPap may also be used to perform initial screening of slides, which are then checked by a technologist. Any abnormal Pap test should be followed by colposcopy, not by double checking the Pap test.

Normal results

Normal (negative) results from the laboratory exam mean that no atypical, dysplastic, or cancer cells were detected, and the cervix is normal.

Abnormal results

Terminology

Abnormal cells found on the Pap test may be described using two different grading systems. Although this can be confusing, the systems are quite similar. The Bethesda system is based on the term "squamous intraepithelial lesion" (SIL). Precancerous cells are classified as atypical squamous cells of undetermined significance, low-grade SIL, or high-grade SIL. Low-grade SIL includes mild dysplasia (abnormal cell growth) and abnormalities caused by HPV; high-grade SIL includes moderate or severe dysplasia and carcinoma in situ (cancer that has not spread beyond the cervix).

Another term that may be used is "cervical intraepithelial neoplasia" (CIN). In this classification system, mild dysplasia is called CIN I, moderate is CIN II, and severe dysplasia or carcinoma in situ is CIN III.

Regardless of terminology, it is important to remember that an abnormal (positive) result does not necessarily indicate cancer. Results may be falsely abnormal after infection or irritation of the cervix. Up to 40% of mild dysplasia reverts to normal tissue without treatment, and only 1% of mild abnormalities ever develop into cancer.

Changes of unknown cause

ASCUS or LSIL cells are found in 5%-10% of all Pap tests. The most common abnormality is atypical squamous cells of undetermined significance, which are found in 4% of all Pap tests. Sometimes these results are described further as either reactive or precancerous. Reactive changes suggest that the cervical cells are responding to inflammation, such as from a yeast infection. These women may be treated for infection and then undergo repeat Pap testing in three to six months. If those results are negative, no further treatment is necessary. This category may also include atypical "glandular" cells, which could imply a more severe type of cancer and requires repeat testing and further evaluation.

Dysplasia

The next most common finding (in about 25 of every 1,000 tests) is low-grade SIL, which includes mild dysplasia or CIN I and changes caused by HPV. Unlike cancer cells, these cells do not invade normal tissues. Women are most susceptible to cervical dysplasia between the ages of 25 and 35. Typically, dysplasia causes no symptoms, although women may experience abnormal vaginal bleeding. Because dysplasia is precancerous, it should be treated if it is moderate or severe.

Treatment of dysplasia depends on the degree of abnormality. In women with no other risk factors for cervical cancer, mild precancerous changes may be simply observed over time with repeat testing, perhaps every four to six months. This strategy works only if women are diligent about keeping later appointments. Premalignant cells may remain that way without causing cancer for five to ten years, and may never become malignant.

In women with positive results or risk factors, the gynecologist must perform colposcopy and biopsy. A colposcope is an instrument that looks like binoculars, with a light and a magnifier, used to view the cervix. Biopsy, or removal of a small piece of abnormal cervical or vaginal tissue for analysis, is usually done at the same time.

High-grade SIL (found in three of every 50 Pap tests) includes moderate to severe dysplasia or carcinoma in situ (CIN II or III). After confirmation by colposcopy and biopsy, it must be removed or destroyed to prevent further growth. Several outpatient techniques are available: conization (removal of a cone-shaped piece of tissue), laser surgery, cryotherapy (freezing), or the "loop electrosurgical excision procedure." Cure rates are nearly 100% after prompt and appropriate treatment of carcinoma in situ. Of course, frequent checkups are then necessary.

Cancer

HPV, the most common STD in the United States, may be responsible for many cervical cancers. Cancer may be manifested by unusual vaginal bleeding or discharge, bowel and bladder problems, and pain. Women are at greatest risk of developing cervical cancer between the ages of 30 and 40 and between the ages of 50 and 60. Most new cancers are diagnosed in women between 50 and 55. Although the likelihood of developing this disease begins to level off for Caucasian women at the age of 45, it increases steadily for African Americans for another 40 years. Biopsy is indicated when any abnormal growth is found on the cervix, even if the Pap test is negative.

Doctors have traditionally used radiation therapy and surgery to treat cervical cancer that has spread within the cervix or throughout the pelvis. In severe cases, postoperative radiation is administered to kill any remaining cancer cells, and chemotherapy may be used if cancer has spread to other organs. Recent studies have shown that giving chemotherapy and radiation at the same time improves a patient's chance of survival. The National Cancer Institute has urged physicians to strongly consider using both chemotherapy and radiation to treat patients with invasive cervical cancer. The survival rate at five years after treatment of early invasive cancer is 91%; rates are below 70% for more severe invasive cancer. That is why prevention, risk reduction, and frequent Pap tests are the best defense for a woman's gynecologic health.

The Pap test is a procedure used to detect abnormal growth of cervical cells which may be a precursor to cancer of the cervix. It is administered by a physician who inserts a speculum into the vagina to open and separate the vaginal walls. A spatula is then inserted to scrape cells from the cervix. These cells are transferred onto glass slides for laboratory analysis. The Pap test may also identify vaginitis, some sexually transmitted diseases, and cancers of the uterus and ovaries.

Resources

PERIODICALS

"American Cancer Society Issues New Early Detection Guidelines." Women's Health Weekly December 19, 2002: 12.

Law, Malcolm. "How Frequently Should Cervical Screening Be Conducted." Important Journal of Medical Screening (Winter 2003): 159-161.

OTHER

"Pap smear: Simple, life-saving test." April 29, 1999. April 26, 2001. [cited June 28, 2001]. 〈http://www.mayohealth.org/home?id=HQ01177〉.

"Pap Smears: The simple test that can save your life." January 29, 2001. April 26, 2001. [cited June 28, 2001]. 〈http://www.mayohealth.org/home?id=HQ01178〉.

KEY TERMS

Carcinoma in situ— Malignant cells that are present only in the outer layer of the cervix.

Cervical intraepithelial neoplasia (CIN)— A term used to categorize degrees of dysplasia arising in the epithelium, or outer layer, of the cervix.

Dysplasia— Abnormal changes in cells.

Human papillomavirus (HPV)— The most common STD in the United States. Various types of HPV are known to cause cancer.

Neoplasia— Abnormal growth of cells, which may lead to a neoplasm, or tumor.

Squamous intraepithelial lesion (SIL)— A term used to categorize the severity of abnormal changes arising in the squamous, or outermost, layer of the cervix.

Pap test

Definition

The Pap test is a procedure in which a physician scrapes cells from the cervix or vagina to check for cervical cancer , vaginal cancer , or abnormal changes that could lead to cancer.

Purpose

The Pap test is used to detect abnormal growth of cervical cells at an early stage so that treatment can be started when the condition is easiest to treat. This microscopic analysis of cells can detect cervical cancer, "precancerous" changes, inflammation (vaginitis), infections, and some sexually transmitted diseases (STDs). The Pap test can occasionally detect endometrial (uterine) cancer or ovarian cancer , although it was not designed for this purpose.

Women should begin to have Pap tests at the age of 18 or whenever they start having sex. Young people are more likely to have multiple sex partners, which increases their risk of certain diseases that can cause cancer, such as human papillomavirus (HPV), but the American Cancer Society suggests the test benefits women of every age. Doctors have varying opinions about how often a woman should have a Pap test. The American Cancer Society states that after three consecutive negative examinations, a doctor may decide that a woman without symptoms of gynecologic problems may be examined less frequently, usually every three years. Many other doctors, however, recommend annual Pap tests for all their patients.

Women with certain risk factors should always have yearly tests. Those at highest risk for cervical cancer are women who started having sex before age 18, those with many sex partners (especially if they did not use condoms, which protect against STDs), those who have had STDs such as genital herpes or genital warts, and those who smoke. Women older than 40 also should have the test yearly, especially in the event of bleeding after menopause. Women who have had a positive test result in the past may need screening every six months. Women who have had cervical cancer or precancer should have regular Pap smears.

Other women also benefit from the Pap test. Women over age 65 account for 25% of all cases of cervical cancer and 41% of deaths from this disease. Women over age 65 who have never had a Pap smear benefit the most from a Pap smear. Even a woman who has had a hysterectomy (removal of the uterus) should continue to have regular Pap tests at the discretion of the woman and the provider. If the surgery was for cancer, she may need to be examined more often than once a year. (Some women have the cervix left in place after hysterectomy.) Finally, a pregnant woman should have a Pap test as part of her first prenatal examination.

The Pap test is a screening test . It identifies women who are at increased risk of cervical dysplasia (abnormal cells) or cervical cancer. Only an examination of the cervix with a special lighted instrument (colposcopy) and samples of cervical tissue (biopsies) can actually diagnose these problems.

Precautions

The Pap test is usually not done during the menstrual period because of the presence of blood cells. The best time is in the middle of the menstrual cycle.

Description

The Pap test is an extremely cost-effective and beneficial test. Cervical cancer used to be a leading cause of cancer deaths in American women, but widespread use of this diagnostic procedure reduced the death rate from this disease by 74% between 1955 and 1992. The Pap test detects about 95% of cervical cancer.

The Pap test, sometimes called a cervical smear, is the microscopic examination of cells scraped from both the outer cervix and the cervical canal. (The cervix is the opening between the vagina and the uterus, or womb.) It is called the "Pap" test after its developer, Dr. George N. Papanicolaou. This simple procedure is performed during a gynecologic examination and is usually covered by insurance. For those with coverage, Medicare will pay for one screening Pap smear every three years.

During the pelvic examination, an instrument called a speculum is inserted into the vagina to open it. The doctor then uses a tiny brush, or a cotton-tipped swab and a small spatula to wipe loose cells off the cervix and to scrape them from the inside of the cervix. The cells are transferred or "smeared" onto glass slides, the slides are treated to stabilize the cells, and the slides are sent to a laboratory for microscopic examination. The entire procedure is usually painless and takes five to ten minutes at most.

Preparation

The Pap test may show abnormal results when a woman is healthy or normal results in women with cervical abnormalities as much as 25% of the time. It may even miss up to 5% of cervical cancers. Some simple preparations may help to ensure that the results are reliable. Among the measures that may help increase test reliability are:

• Avoiding sexual intercourse for two days before the test.
• Not using douches for two or three days before the test.

• Avoiding using tampons, vaginal creams, or birth control foams or jellies for two to three days before the test.
• Scheduling the Pap smear when not menstruating.

However, most women are not routinely advised to make any special preparations for a Pap test.

If possible, women may want to ensure that their test is performed by an experienced gynecologist, physician, or provider and sent to a reputable laboratory. The physician should be confident in the accuracy of the chosen lab.

Before the exam, the physician will take a complete sexual history to determine a woman's risk status for cervical cancer. Questions may include date and results of the last Pap test, any history of abnormal Pap tests, date of last menstrual period and any irregularity, use of hormones and birth control, family history of gynecologic disorders, and any vaginal symptoms. These topics are relevant to the interpretation of the Pap test, especially if any abnormalities are detected. Immediately before the Pap test, the woman should empty her bladder to avoid discomfort during the procedure.

Aftercare

Harmless cervical bleeding is possible immediately after the test; a woman may need to use a sanitary napkin. She should also be sure to comply with her doctor's orders for follow-up visits.

Risks

No appreciable health risks are associated with the Pap test. However, abnormal results (whether valid or due to technical error) can cause significant anxiety. Women may wish to have their sample double-checked, either by the same laboratory or by the new technique of computer-assisted rescreening. The Food and Drug Administration (FDA) has approved the use of Auto Pap and PAPNET to doublecheck samples that have been examined by technologists. AutoPap may also be used to perform initial screening of slides, which are then checked by a technologist. Any abnormal Pap test should be followed by colposcopy and not by double checking the Pap test.

Normal results

Normal (negative) results from the laboratory exam mean that no atypical, dysplastic, or cancer cells were detected, and the cervix is normal.

Abnormal results

Terminology

Abnormal cells found on the Pap test may be described using two different grading systems. Although this can be confusing, the systems are quite similar. The "Bethesda" system is based on the term "squamous intraepithelial lesion" (SIL). Precancerous cells are classified as "atypical squamous cells of undetermined significance, " "low-grade" SIL, or "high-grade" SIL. Low-grade SIL includes mild dysplasia (abnormal cell growth) and abnormalities caused by HPV; high-grade SIL includes moderate or severe dysplasia and carcinoma in situ (cancer that has not spread beyond the cervix).

Another term that may be used is "cervical intraepithelial neoplasia" (CIN). In this classification system, mild dysplasia is called CIN I, moderate is CIN II, and severe dysplasia or carcinoma in situ is CIN III.

Regardless of terminology, it is important to remember that an abnormal (positive) result does not necessarily indicate cancer. Results may be falsely abnormal after infection or irritation of the cervix. Up to 40% of mild dysplasia reverts to normal tissue without treatment, and only 1% of mild abnormalities ever develop into cancer.

Treatment

CHANGES OF UNKNOWN CAUSE.

The most common abnormality is atypical squamous cells of undetermined significance (ASCUS), which are found in 4% of all Pap tests. Sometimes these results are described further as either reactive or precancerous. Reactive changes suggest that the cervical cells are responding to inflammation, such as from a yeast infection. These women may be treated for infection and then undergo repeat Pap testing in three to six months. If those results are negative, no further treatment is necessary. This category may also include atypical "glandular" cells, which could imply a more severe type of cancer and requires repeat testing and further evaluation.

DYSPLASIA.

The next most common finding (in about 25 of every 1, 000 tests) is low-grade SIL, which includes mild dysplasia or CIN I and changes caused by HPV. Unlike cancer cells, these cells do not invade normal tissues. Women are most susceptible to cervical dysplasia between the ages of 25 and 35. Typically, dysplasia causes no symptoms, although women may experience abnormal vaginal bleeding. Because dysplasia is precancerous, it should be treated if it is moderate or severe.

Treatment of dysplasia depends on the degree of abnormality. In women with no other risk factors for cervical cancer, mild precancerous changes may be simply observed over time with repeat testing, perhaps every four to six months. This strategy works only if women are diligent about keeping later appointments. Premalignant cells may remain that way without causing cancer for five to ten years, and may never become malignant.

In women with positive results or risk factors, the gynecologist must perform colposcopy and biopsy . A colposcope is an instrument that looks like binoculars, with a light and a magnifier, used to view the cervix. Biopsy, or removal of a small piece of abnormal, cervical or vaginal tissue for analysis, is usually done at the same time.

High-grade SIL (found in three of every 50 Pap tests) includes moderate to severe dysplasia or carcinoma in situ (CIN II or III). After confirmation by colposcopy and biopsy, it must be removed or destroyed to prevent further growth. Several outpatient techniques are available: conization (removal of a cone-shaped piece of tissue), laser surgery, cryotherapy (freezing), or the "loop electrosurgical excision procedure." Cure rates are nearly 100% after prompt and appropriate treatment of carcinoma in situ. Of course, frequent checkups are then necessary.

CANCER.

HPV, the most common STD in the United States, may be responsible for many cervical cancers. Cancer may be manifested by unusual vaginal bleeding or discharge, bowel and bladder problems, and pain. Women are at greatest risk of developing cervical cancer between the ages of 30 and 40 and between the ages of 50 and 60. Most new cancers are diagnosed in women between 50 and 55. Although the likelihood of developing this disease begins to level off for Caucasian women at the age of 45, it increases steadily for African-Americans for another 40 years. Biopsy is indicated when any abnormal growth is found on the cervix, even if the Pap test is negative.

Doctors have traditionally used radiation therapy and surgery to treat cervical cancer that has spread within the cervix or throughout the pelvis. In severe cases, postoperative radiation is administered to kill any remaining cancer cells, and chemotherapy may be used if cancer has spread to other organs. Recent studies have shown that giving chemotherapy and radiation at the same time improves a patient's chance of survival. The National Cancer Institute has urged physicians to strongly consider using both chemotherapy and radiation to treat patients with invasive cervical cancer. The survival rate at five years after treatment of early invasive cancer is 91%; rates are below 70% for more severe invasive cancer. That is why prevention, risk reduction, and frequent Pap tests are the best defense for a woman's gynecologic health.

Resources

BOOKS

Berek, Jonathan S., Eli Y. Adashi, and Paula A. Hillard. Novak's Gynecology. 12th ed. Baltimore: Williams & Wilkins, 1996.

Schull, Patricia. Illustrated Guide to Diagnostic Tests. 2nd ed. Springhouse, PA: Springhouse Corporation, 1998.

Slupik, Ramona I., ed. American Medical Association Com plete Guide to Women's Health. New York: Random House, 1996.

PERIODICALS

Kennedy, A.W. "What do you recommend for a patient with a Pap smear indicating atypical cells?" Cleveland Clinic Journal of Medicine 67, no. 9 (2000).

Morgan, Peggy, and Linda Rao. "Abnormal Pap? What to Do Next." Prevention 48 (November 1996): 90-6.

"Patient info: why you need a Pap test." Patient Care 33, no. 12 (1999).

Perlmutter, Cathy, and Toby Hanlon. "The Smart Pap: How to Wage a Successful Smear Campaign to Improve the Accuracy of Your Results." Prevention 48 (October 1996): 82-5, 155-7.

"Topics in Women's Health—Contending with the Abnormal Pap test." Patient Care 33, no. 12 (1999).

ORGANIZATIONS

American College of Obstetricians and Gynecologists. 409 12th St. SW, PO Box 96920, Washington, DC 20090-6920. (202) 863-2518. <http://www.acog.com>.

National Cancer Institute, Office of Communications. 31 Center Dr., MSC 2580, Bethesda, MD 20892-2580. (800) 4-CANCER. <http://cancernet.nci.nih.gov/>.

OTHER

"Pap Smears: The simple test that can save your life." 29 Jan. 2001. 26 Apr. 2001. 28 June 2001 <www.mayohealth.org/home?id=HQ01178>.

"Pap smear: Simple, life-saving test." 29 Apr. 1999. 26 Apr. 2001. 28 June 2001. <www.mayohealth.org/home?id=HQ01177>.

Laura J. Ninger

KEY TERMS

Carcinoma in situ

—Malignant cells that are present only in the outer layer of the cervix.

Cervical intraepithelial neoplasia (CIN)

—A term used to categorize degrees of dysplasia arising in the epithelium, or outer layer, of the cervix.

Dysplasia

—Abnormal changes in cells.

Human papillomavirus (HPV)

—The most common STD in the United States. Various types of HPV are known to cause cancer.

Neoplasia

—Abnormal growth of cells, which may lead to a neoplasm, or tumor.

Squamous intraepithelial lesion (SIL) —A term used to categorize the severity of abnormal changes arising in the squamous, or outermost, layer of the cervix.

Pap Test

Definition

The Papanicolaou (Pap) test involves scraping cells from the cervix (the lower narrow portion of the uterus that connects to the vagina) and examining them under a microscope for signs of cervical cancer or abnormal cells that could lead to cancer .

Purpose

Pap tests, also referred to as cervical smears or cervical/vaginal cytology, can detect abnormal cervical cells before they develop into cancer cells. Pap tests also detect cervical cancer in its early stages when it is easier to treat, as well as noncancerous conditions such as infection and inflammation. Most cases of invasive cervical cancer can be prevented by regular Pap tests. Since 1950 new cases of and deaths from cervical cancer have declined sharply due to widespread screening with the Pap test. Deaths from cervical cancer are as of 2008 rare in women of any age who have regular Pap tests. Of American women diagnosed with cervical cancer, 60% had not had a Pap test in the previous five years.

Almost all cervical cancers are caused by persistent infection with the human papillomavirus (HPV), which is spread through sexual contact. However, temporary

HPV infections and insignificant cervical cell changes are very common, and it takes years for significant abnormalities or cancer to develop. Therefore, Pap tests should be performed at least once every three years, starting about three years after a woman begins having sexual intercourse but no later than age 21.

If Pap tests between the ages of 55 and 65 are normal, women are often advised that no further screening is necessary. Women who have a negative Pap test at age 60 or older are very unlikely to have a subsequent abnormal Pap. Women aged 65 and over who have never had a Pap test are advised to have two tests one year apart: if both tests are normal, no further testing is necessary.

Pap tests are not useful in women who have had a total hysterectomy in which the uterus and cervix were removed unless the surgery was for cervical pre-cancer or cancer. These women should be tested annually for vaginal cancer until they have had three normal test results.

Precautions

Pap tests miss up to 20% of cervical cell abnormalities. Such false-negative results may delay treatment even in the presence of symptoms of cervical cancer. However, since changes in cervical cells occur very slowly, abnormalities should be detected in a subsequent Pap test within the next three years.

False-positive results occur when cells appear abnormal although no cancer is present. Some abnormal cervical cells never become cancerous. False-positive results can cause anxiety and lead to more tests and procedures which have their own risks.

Description

Pap tests are performed in doctors' offices, clinics, local health departments, and hospitals, usually in the course of a pelvic examination. The woman lies on an exam table with a sheet over her legs and stomach, her feet in holders called stirrups, and her knees open. A female staffer is always present. A plastic or metal instrument called a speculum is used to widen the vagina so that the upper part of the vagina and cervix are visible. Cells are scraped from the surface of the cervix and vagina using a piece of cotton, a small cervical brush, or a small wooden scraper or stick.

The cells are placed on a microscope slide, treated with fixative, and sent to a laboratory. The cells are examined under a microscope to look for abnormalities. With a new liquid-based, thin-layer slide preparation, the brush or other collection device is rinsed in a vial of liquid preservative and the vial is sent to the lab where an automated device prepares the slide. This eliminates background material and provides a thin layer of cells for analysis. Studies suggest that this procedure is more sensitive than the traditional Pap smear. Computer-automated readers can send the image to a computer for analysis. Sometimes an HPV DNA test to detect strains of HPV associated with cervical cancer is performed at the same time as the Pap test.

Preparation

Pap tests should not be performed during menstruation. The best time for a Pap test is 10 to 20 days after the first day of the last menstrual period. Women should avoid douching or using vaginal medicines or deodorants, spermicidal foams, creams, or jellies, or tampons for about two days before a Pap test since these products can disguise or wash away abnormal

cells. Women should avoid sexual intercourse for 48 hours before a Pap test to avoid inconclusive results that may require retesting.

Aftercare

Following a Pap test a woman may immediately resume her normal activities.

Complications

Some Pap tests are unreadable and need to be repeated due to the following:

• too few cells in the specimen
• clumped cells
• obscuring by blood or mucus.

Results

Lab reports

Pap-test results come back from the laboratory in one to two weeks. Most U.S. laboratories use the Bethesda System for reporting Pap-test results:

• “Negative for intraepithelial lesion or malignancy” is a normal result meaning that no abnormal cells were found on the surface of the cervix.
• Atypical squamous cells of undetermined significance (ASC-US) indicates that the squamous cells—the flat thin cells that line the surface of the cervix—do not appear completely normal, perhaps due to HPV infection, but the significance of the abnormality is unknown.
• Atypical squamous cells-H (ASC-H) indicates that the cells are atypical, and although the significance is unclear, a precancerous high-grade squamous intraepithelial lesion (SIL) cannot be excluded.
• Atypical glandular cells (AGC) indicates that the mucus-producing cells in the endocervical canal (the opening at the center of the cervix) or in the lining of the uterus do not appear normal, but the significance of the change is unclear.
• Endocervical adenocarcinoma-in-situ (AIS) means that precancerous cells are found in the glandular or mucus-producing tissue.
• Low-grade squamous intraepithelial lesion (LSIL) indicates early changes in the size and shape of the squamous cells caused by HPV infection.
• High-grade squamous intraepithelial lesion (HSIL) indicates markedly abnormal or precancerous cells with a higher probability of progressing to invasive cervical cancer.
• Cancer cells are present.

Healthcare providers may use slightly different terms to describe abnormal Pap-test results:

• Dysplasia indicates the presence of abnormal cells which could develop into very early cervical cancer. It is categorized as mild, moderate, severe, or carcinoma-in-situ (CIS) (cancer cells confined to the surface of the cervix) depending on the degree of abnormality; mild dysplasia is a LSIL and moderate to severe dysplasia or CIS is an HSIL.
• Cervical intraepithelial neoplasia (CIN) indicates abnormal growth of cells on the surface of the cervix. It is categorized as CIN-1 to 3 depending on the severity; CIN-1 is equivalent to a LSIL or mild dysplasia; CIN-2 and -3 are HSIL, moderate to severe dysplasia, or CIS.
• Cervical cancer indicates that cancer cells have spread deeper into the cervix.
• Invasive cervical cancer means that cancer cells have spread to other tissues or organs.

Follow-up

Cervical cells can undergo changes for many reasons other than cancer, including the following:

• inflammation
• bacterial, viral, or yeast infection
• growths such as benign polyps or cysts
• hormone changes due to pregnancy or menopause.

Of about 55 million Pap tests performed annually in the United States, about 3.5 million or 6% are abnormal and require medical follow-up. The Pap test may be repeated, particularly if the results are ambiguous or indicate only a minor abnormality, since abnormal cervical cells often disappear without treatment. Cell changes are often caused by low hormone levels. An ACS-US result in a woman who is near or past menopause can often be cleared up with the application of an estrogen cream to the cervical surface for a few weeks. Following two normal Pap results women can return to routine Pap tests every three years.

ASC-US, ASC-H, LSIL, or HSIL Pap results are often followed by colposcopy, in which the cervix is coated with a dilute vinegar solution that turns abnormal cells white and a lighted magnifying instrument called a colposcope is used to examine the vagina and cervix.

An HPV DNA test may be performed to determine whether the abnormal cells are the result of infection with an HPV that is linked to cervical cancer. A large clinical trial has indicated that testing a cervical sample for HPV is more efficient than colposcopy or a repeat Pap test for identifying ASC-US abnormalities that require treatment. It was expected as of 2008 that HPV tests may replace Pap tests for routine cervical cancer screening.

QUESTIONS TO ASK YOUR DOCTOR

• How often should I have a Pap test?
• Now that I am 60 do I still need to have Pap tests?
• Should I be tested for HPV?
• When will I learn the results of my Pap test?
• What do my Pap-test results mean?
• What will the treatment be?
• Should I have another Pap test or get a second opinion?

If colposcopy reveals abnormal cells, the cervix may be examined with a LUMA Cervical Imaging System, which shines a light on the cervix. Normal and abnormal cells respond differently to the light and the system produces a colored map that distinguishes between them.

If these procedures indicate the presence of cells that may be precancerous, various additional tests and procedures may be utilized to diagnose and treat the condition.

Care team concerns

Pap tests are performed by the following:

• physicians
• physician assistants
• nurse-midwives
• nurse practitioners
• women's healthcare specialists.

A pathologist supervises the examination of the Pap smear for abnormalities.

Resources

BOOKS

Comprehensive Cervical Cancer Control: A Guide to Essential Practice. Geneva: World Health Organization, 2006.

Hoda, Rana S., and Syed A. Hoda. Fundamentals of PAP Test Cytology. Totowa, NJ: Humana Press, 2007.

Rushing, Lynda, and Nancy Joste. Abnormal Pap Smears: What Every Woman Needs to Know. Amherst, NY: Prometheus, 2008.

Sutton, Amy L. Cancer Sourcebook for Women, 3rd ed. Detroit: Omnigraphics, 2006.

KEY TERMS

AGC —Atypical glandular cells; a Pap-test result indicating that mucus-producing cells in the cervix or lining of the uterus appear abnormal.

AIS —Endocervical adenocarcinoma-in-situ; a Pap test result indicating precancerous cells in the glandular or mucus-producing tissue of the cervix.

ASC-H —Atypical squamous cells; a Pap-test finding of atypical cells of unknown significance with the possibility of a precancerous high-grade squamous intraepithelial lesion.

ASC-US —Atypical squamous cells of undetermined significance; a Pap-test result.

Carcinoma-in-situ (CIS) —Cancer cells confined to the surface of the cervix.

Cervix —The lower narrow part of the uterus that opens to the vagina.

CIN —Cervical intraepithelial neoplasia; abnormal growth of cells on the surface of the cervix.

Colposcopy —The use of a magnifying instrument to examine the vagina and cervix.

Dysplasia —Growth of abnormal cells.

Endocervical canal —The opening at the center of the cervix.

HPV —Human papillomavirus, some strains of which cause warts and others can cause cervical cancer.

HSIL —High-grade squamous intraepithelial lesion; moderate to severe dysplasia; a Pap-test finding of abnormal or precancerous cells with a higher probability of progressing to invasive cervical cancer.

Intraepithelial —On the surface of the cervix.

Lesion —Abnormal cells.

LSIL —Low-grade squamous intraepithelial lesion; mild dysplasia; a Pap-test finding of early changes in the size and shape of squamous cells.

Neoplasia —Tumor formation.

SIL —Squamous intraepithelial lesion; abnormal squamous cells on the surface of the cervix.

Speculum —An instrument used to widen the vagina so that a Pap test can be performed.

Squamous —Small scale-like cells on the surface of the cervix.

PERIODICALS

Runowicz, C. D. “Molecular Screening for Cervical Cancer—Time to Give Up Pap Tests?” New England Journal of Medicine 357, no. 16 (October 16, 2007):1650–1653.

Sirovich, Brenda E., et al. “Screening for Cervical Cancer: Will Women Accept Less?” American Journal of Medicine 118, no. 2 (February 2005): 151.

OTHER

“Cervical Cancer Screening.” National Cancer Institute December 19, 2007 [cited March 3, 2008]. http://www.cancer.gov/cancertopics/pdq/screening/cervical/Patient/page1.

“Pap Smear.” Lab Tests Online March 23, 2005 [cited March 4, 2008]. http://www.labtestsonline.org/understanding/analytes/pap/glance.html.

“Pap Test.” The National Women's Health Information Center March 2006 [cited March 4, 2008]. http://womenshealth.gov/faq/pap.htm.

“The Pap Test: Questions and Answers.” National Cancer Institute March 29, 2007 [cited March 4, 2008]. http://www.cancer.gov/cancertopics/factsheet/Detection/Pap-test.

ORGANIZATIONS

National Breast and Cervical Cancer Early Detection Program, Centers for Disease Control and Prevention, Division of Cancer Prevention and Control, 4770 Buford Hwy. NE, MS K-64, Atlanta, GA, 30341-3717, (800) CDC-INFO, (770) 488-4760, [email protected], http://www.cdc.gov/cancer/NBCCEDP/about.htm.

National Cancer Institute, NCI Public Inquiries Office, 6116 Executive Blvd., Room 3036A, Bethesda, MD, 20892 8322, (800) 4-CANCER, http://www.cancer.gov.

Planned Parenthood Federation of America, 434 West Thirty-third Street, New York, NY, 10001, (212) 541-7800, (800) 230-7526, (212) 245-1845, http://www.ppfa.org.

Margaret Alic Ph.D.