Colorectal Cancer Screening (PDQ®): Screening - Patient Information [NCI] - Risks of Colorectal Cancer Screening
Screening tests have risks.
Decisions about screening tests can be difficult. Not all screening tests are helpful and most have risks. Before having any screening test, you may want to discuss the test with your doctor. It is important to know the risks of the test and whether it has been proven to reduce the risk of dying from cancer.
Treatment decisions should be made with reference to the TNM classification system, rather than the older Dukes or the Modified Astler-Coller classification schema.
The American Joint Committee on Cancer (AJCC) and a National Cancer Institute-sponsored panel recommended that at least 12 lymph nodes be examined in patients with colon and rectal cancer to confirm the absence of nodal involvement by the tumor.[2,3,4] This recommendation takes into consideration that the number of lymph nodes examined...
Screening test results may appear to be normal even though colorectal cancer is present. A person who receives a false-negative test result (one that shows there is no cancer when there really is) may delay seeking medical care even if there are symptoms.
False-positive test results can occur.
Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isn't) can cause anxiety and is usually followed by more tests (such as biopsy), which also have risks.
The following colorectal cancer screening tests have risks:
The results of fecal occult blood testing may appear to be abnormal even though no cancer is present. A false-positive test result can cause anxiety and lead to more testing, including colonoscopy or barium enema with sigmoidoscopy.
There can be discomfort or pain during sigmoidoscopy. Women may have more pain during the procedure, which may lead them to avoid future screening. Tears in the lining of the colon and bleeding also may occur.
Serious complications from colonoscopy are rare, but can include tears in the lining of the colon, bleeding, and problems with the heart or blood vessels. These complications may occur more often in older patients.
Virtual colonoscopy often finds problems with organs other than the colon, including the kidneys, chest, liver, ovaries, spleen, and pancreas. Some of these findings lead to more testing. The risks and benefits of this follow-up testing are being studied.
Your doctor can advise you about your risk for colorectal cancer and your need for screening tests.