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Dr. Roach: Fecal immune test can be a sensitive colon cancer detector

Keith Roach
To Your Health

Dear Dr. Roach: I am a 74-year-old male, and I recently received a negative result from my mail-in fecal test. I have been on an every-five-years colonoscopy cycle for the past 20 years (noncancerous polyps were always found) and since my colorectal surgeon recently retired, I decided to use the FIT. Since then, I have been told that the FIT is not reliable for those on my cycle. With my insurance plan, which has a high out of pocket, I would be paying the full colonoscopy cost if polyps are found (no cost if no polyps, since it is considered a different procedure). My question is: Can I rely on the FIT results?

Dr. Keith Roach

R.D.

Dear R.D.: A FIT test is a fecal immunochemical test for blood. It is superior to the standard guiaic tests (stool cards) that have been done for many years because it can find more cases of colon cancer, and has no more false-positive tests.

Because it is quite sensitive, a negative test means it is unlikely you have colon cancer. One study estimated that in an average-risk population, a person with a negative FIT test is 94% likely NOT to have any kind of advanced precancerous polyp and 99.9% likely not to have colon cancer.

In the U.S., FIT tests are usually used every year, while in other countries, every two to three years is common. I cannot comment on what your insurance plan will pay for, but repeatedly negative FIT tests are good evidence that you do not have colon cancer. The colonoscopy remains the most commonly recommended choice for colon cancer screening, but FIT tests or combination FIT and genetic tests are a reasonable choice for people who do not want colonoscopy or who are not good candidates.

Dear Dr. Roach: I am a healthy 62-year-old woman. I do not eat meat, have a plant-based diet, and exercise five days per week. My mother had breast cancer and her brother had prostate cancer. My father had prostate cancer and his sister had breast cancer. I have read that there is a genetic link between prostate and breast cancer. I tested negative for the BRCA 1 and 2 gene mutations, but am concerned because most women who get breast cancer are not positive for BRCA 1 and 2. Is there anything else I can do or other tests I can have to decrease my chances of getting breast cancer?

M.B.

Dear M.B.: Given your first-degree relative (mother) had breast cancer, you are indeed at higher-than-average risk. You certainly should be getting regular mammograms to screen for breast cancer. This can allow for early detection and treatment. Women at very high risk are sometimes offered MRI screening plus mammography. This can have an improved detection rate, but at a cost of more false positive results, which increase anxiety and often necessitate biopsy.

However, you asked about prevention of cancer in the first place. The well-established lifestyle factors are restricting exposure to alcohol (a modest risk factor) and smoking (even secondhand smoking is a significant risk factor). There is some evidence that working the night shift increases breast cancer risk, but this is contradicted by other data. Being overweight or obese increases breast cancer risk, probably through higher blood estrogen levels.

Regular physical activity was associated with a decreased risk of breast cancer compared with being sedentary. A Mediterranean diet, with less meat and more fruits, legumes, vegetables and nuts than a typical Western diet seemed to show a reduced risk of breast cancer.

Finally, some women at high risk for breast cancer use medication to reduce risk.

Raloxifene is one common one.

Readers may email questions to ToYourGoodHealth@med.cornell.edu