MYTH: All colorectal cancers arise from diseased polyps.
FACT: A recent study has found that flat and depressed growths on the colon wall are more common than polyps, and 10 times more likely than polyps to be malignant. These nonpolypoid lesions don't develop into polyps, and are difficult to spot because they're smaller and blend in with surrounding tissue. They may explain cancer that occurs between colonoscopies. Researchers say the flat and depressed growths highlight the importance of high-quality colonoscopy screening.1
MYTH: All types of colon polyps cause cancer.
FACT: Adenomatous polyps account for up to 50% of colon polyps. Large or multiple polyps raise the risk of colorectal cancer if they're not removed.
MYTH: Colorectal cancer is most common in non-Hispanic white men.
FACT: African-American men and women are at higher risk for colorectal cancer than other racial groups, for reasons that aren't yet understood.
MYTH: Colonoscopy is the only way to screen for colorectal cancer.
FACT: Besides colonoscopy, which is the gold standard, several screening tests are available for colorectal cancer, including the fecal occult blood test, the immunochemical fecal occult blood test, flexible sigmoidoscopy, double-contrast barium enema, and computed tomography colonography ("virtual colonoscopy"). The American Cancer Society (ACS) has developed colorectal screening guidelines based on risk.
MYTH: Colon cancer is always fatal.
FACT: When colon cancer is caught early, the 5-year survival rate is 93%, so screening saves lives. The survival rate is about the same for rectal cancer. When the cancer spreads to the liver, only 9% of patients survive, although treatment options are improving.
MYTH: Irritable bowel syndrome is a risk factor for colorectal cancer.
FACT: Irritable bowel syndrome is a functional disorder and doesn't progress to colorectal cancer. However, a history of inflammatory bowel disease (such as ulcerative colitis and Crohn's disease) increases the risk of developing colorectal cancer. Patients with inflammatory bowel disease need to be screened more frequently for colorectal cancer, as advised by their health care provider.
MYTH: Chemotherapy is the main treatment for colon cancer.
FACT: Surgery is the main treatment for colon cancer, according to the ACS. The most common surgical procedure is segmental resection, which removes the diseased portion of the colon and the nearby lymph nodes. Typically, between one-fourth and one-third of the colon is removed, but the amount may be more or less depending on the size and location of the cancer. The remaining sections of the colon are then reattached.
1. Soetikno RM, et al. Prevalence of nonpolypoid (flat and depressed) colorectal neoplasms in asymptomatic and symptomatic adults. JAMA. 299(9):1027-1035, March 5, 2008. [Context Link]
American Cancer Society. http://www.cancer.org.
University of Michigan Health System. 12 myths about colon cancer. http://www.med.umich.edu/opm/newspage/2007/12myths.htm.
University of Texas M.D. Anderson Cancer Center. Colorectal cancer. http://www.mdanderson.org/diseases/colorectal.