No one looks forward to a colonoscopy, but it can save your life. So you might be wondering whether a home test is a good alternative.
These tests involve mailing a stool sample to a lab. Older types of tests check for blood, which could signal a cancerous growth. Precancerous polyps are harder to find with these tests, because they tend not to bleed. Newer types of stool tests look for changes in DNA that could be signs of cancer. They’re also better at finding advanced polyps. You’ll need to have a colonoscopy if a home test shows any positive results.
Because they can’t detect a problem as early as imaging does, home stool tests are typically appropriate for people who have only an average risk of colorectal cancer and no history of polyps or colon disease.
Imaging tests, on the other hand, can find very small polyps, which can then be removed and tested for cancer. And they don’t need to be repeated as often as home stool tests, which must be done every one to three years. Imaging tests are repeated every five to 10 years, depending on the type of imaging done and whether any polyps are found.
There are differences among imaging tests, but all involve bowel prep. With a traditional colonoscopy, a flexible tube with an attached camera internally examines the entire colon. Flexible sigmoidoscopy is similar, but reaches only part of the colon. Another option is a “virtual” colonoscopy, which is noninvasive. It allows the doctor to see your colon from outside your body, but if any polyps are seen, you’ll need a traditional colonoscopy to remove them.
Despite these different choices, a very real problem exists, experts warn: Many people are still not having any type of colorectal cancer screening. If you’ve been putting it off, take the first step and talk to your doctor about your options.
The U.S. National Cancer Institute has more on all colon cancer screening options.