colon cancer, cancer of any part of the colon (often called the large intestine). Colon cancer is the second most common cancer diagnosed in the United States. Epidemiological evidence has shown that a diet high in fat and low in fruits, vegetables, and fiber contributes to the development of the disease. Smoking is also a factor in some types of colon cancer. Statistically, a family history of colon cancer or cancer of the female reproductive organs, a history of colon polyps, or a history of ulcerative colitis puts one at a greater risk of developing colon cancer. Colon cancer is most common in people over age 50.
Several genes that signal a hereditary predisposition to colon cancer have been identified. For example, mutations in either of two genes, MSH2 and MLH1, can predispose a person to hereditary nonpolyposis colorectal cancer (HNPCC). People in HNPCC families can undergo blood tests that can tell them whether they have an affected gene. With the information obtained from such screening, an appropriate course of preventive measures and follow-up tests can be initiated (see genetic testing).
A sudden change in bowel habits or blood in the feces (often detectable only in a laboratory) may be the first symptoms of colon cancer. In the early stages of the disease there may be no obvious symptoms. Diagnosis is made by physical examination of the rectum and a laboratory examination of blood for carcinoembryonic antigen (CEA), a tumor marker produced by colon cancers. These may be followed by an endoscopic examination of the colon with a sigmoidoscope (to examine the rectum and the adjoining sigmoid colon) or colonoscope (to examine the entire colon). A biopsy of any suspicious tissue, such as a polyp or a flat or depressed lesion, is then examined in a laboratory to determine if cancerous changes are present. If cancer is found, the patient is evaluated to determine the extent of the primary tumor and whether the disease has spread throughout the body.
Treatment depends upon the stage of the cancer. The initial treatment is usually local excision of the tumor or excision of a larger part of the colon followed by the joining of the two adjacent ends, a procedure referred to as end-to-end anastomosis. In some cases a colostomy (an opening that allows waste to be expelled through an opening in the abdomen rather than through the anus) is created either temporarily, to allow healing, or permanently, if significant portions of the colon have had to be removed. If the disease is advanced, radiation therapy, chemotherapy, or biological therapies (therapies that stimulate the body's own immune defenses against the disease) may be used in addition to surgery.
See publications of the National Cancer Institute, the American Cancer Society, and the United Ostomy Association.
"colon cancer." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (December 16, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/colon-cancer
"colon cancer." The Columbia Encyclopedia, 6th ed.. . Retrieved December 16, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/colon-cancer
Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:
Modern Language Association
The Chicago Manual of Style
American Psychological Association
- Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
- In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.