Trending
Dear Dr. Roach: I'm an 85-year-old woman. I took the Cologuard test a month ago, and it came back positive. My gastrointestinal doctor said that at my age, he wouldn't perform a colonoscopy. I asked for other alternatives, and he said that there's a virtual colonoscopy CT scan. I had soft tissue sarcoma a year ago and have been getting CT scans of my pelvic area and chest. My blood work is all good, as well as my tests. What are your feelings on the CT colon scans? -- M.K.
Answer: I understand why you're concerned. When a test like Cologuard is positive, there's a significant risk of colon cancer. The best estimate of your risk of having an advanced polyp now is approximately 38%, and the likelihood that you have actual colon cancer is about 4%.
I do understand why your gastroenterologist is concerned about a colonoscopy. The risk of an adverse event in people who are in their 80s is significantly higher. Both the sarcoma and radiation treatment that you received might increase your specific risk even higher than other people. I will say for my other readers (especially my clinician readers), the person who's ordering Cologuard should've thought carefully about what to do with a positive result before ordering it.
If you're willing to live with a 4% risk of colon cancer, you can stop where you are. Since you've had many CT scans (called a virtual colonography) of your abdomen, including at least one recently, it's reassuring that you probably don't have advanced colon cancer. The blood tests likewise give a measure of reassurance but aren't definitive.
I recommend caution with a virtual CT scan because they're uncomfortable for many people. Also, if it's positive, you're still left unsure as to what to do about it. I'd ask the gastroenterologist whether he'd perform a colonoscopy if the virtual colonography showed a significant concern.
If the answer is still "no," you should, again, consider no further evaluation; however, if he said that he'd do the colonoscopy with a positive CT scan, then you could decide to get it done. But you should recognize that this decision puts you on a path to a risk of a complication, which is about 1%.
The most-common complication is perforation of the colon, which requires a hospital stay. A 4% risk of cancer is still higher than a 1% risk of perforation. A colonoscopy remains the best way to evaluate for cancer and obtain a biopsy of any suspicious mass or polyp.