Coming to Colon Cancer Screening: Simple Home Test

Starting tomorrow, millions of people who have avoided colon cancer screening can get a new home test that's noninvasive and doesn't require the icky preparation most other methods do. Cologuard, developed at the Mayo Clinic, is the first to look for cancer-related DNA in stool. But deciding whether to get it is a more complex choice than ads for "the breakthrough test ... that's as easy as going to the bathroom" make it seem. On one hand, the test could greatly boost screening for a deadly disease that too few people get checked for now. On the other hand, it could lure people away from colonoscopies and other tests that, unlike the new one, have been shown to save lives. "It looks promising," but its impact on cancer risk and survival isn't known, said Dr. Barnett Kramer, a National Cancer Institute screening expert. The details:

• Many current stool tests look for blood that could suggest a tumor. Cologuard does this plus detects DNA that could be a sign of cancer or polyps. If the test is positive, the next step is a colonoscopy.
• Cologuard is being marketed as an alternative to colonoscopy. A large study compared Cologuard to one of the older stool blood tests and found it detected 92% of colorectal cancers and 42% of advanced precancerous growths compared to 74% of cancers and 24% of growths for the older test.
• Cologuard also had a downside—more false alarms. It correctly ruled out colon cancer only 87% of the time versus 95% for the older test. It leads 13% to have follow-up colonoscopies they didn't need. Yet if the alternative is to screen everyone with a colonoscopy in the first place, Cologuard could avoid 87% of them.
• Medicare covers Cologuard but private insurers aren't covering it yet.

(More colon cancer stories.)