Colon cancer screening guidelines from the US Preventive Services Taskforce, the American Cancer Society and gastroenterology organizations call for most adults to get screened starting at age 45 and continuing through age 75.
The most accurate screening test is colonoscopy, which is 94% accurate. It is recommended for people who are at high risk for colon cancer because of family history, personal history of polyps in the colon (which can turn into cancer) or a genetic predisposition to colon cancer.
Problem: Despite the guidelines—and the fact that screening saves lives—40% of eligible people don’t get screened. Why? Many of them don’t want to go through the onerous bowel-cleansing regimen the night before the procedure.
There are other easier—although less accurate—options available. But if the results of one of these tests are positive, you’ll still need to have a colonoscopy.
Fecal immunochemical test (FIT): This test looks for hidden blood in your stool, which suggests polyps or even cancer. Your doctor will give you a FIT test kit to use at home. You take a small sample of stool, and mail it to a lab to be analyzed. You don’t need to do any prep. The cost of the annual test is covered by insurance and Medicare. FIT has an almost 80% accuracy rate for detecting colon cancer, but it detects only about 28% of advanced polyps that might turn into cancer.
Cologuard. This screening kit looks for hidden blood as well as altered DNA in stool. Your doctor will order the test, and you will receive the collection kit in the mail. You do the test at home every three years and send stool samples to Cologuard via UPS. No special prep or change to your diet or medication schedule is required. Cologuard, which is covered by Medicare and most insurers, detects 92% of colon cancers but only 42% of large precancerous polyps. It also may provide a false-positive—indicating that you might have cancer when you don’t.
Blood test. In 2016, the Food and Drug Administration approved the Epi proColon test that looks for circulating DNA and markers of colon cancer in blood. This “liquid biopsy” is offered to people who refuse other forms of screening. While relatively sensitive for detecting late-stage cancer, the test’s sensitivity for detecting early-stage cancer or polyps in the colon is low. For this reason and because of its high false-positive rate, this test is not recommended in the screening guidelines, and the cost is not covered by Medicare or private insurers.