Colon cancer screening - Going 'Back To The Future'?

Armen Hareyan's picture

Colon cancer screening rates continue to lag behind those for breast and cervical cancer. In an editorial in the Feb. 20 edition of the Annals of Internal Medicine, Indiana University School of Medicine gastroenterologist and Regenstrief Institute, Inc. researcher Thomas Imperiale, M.D., writes that to increase screening rates for colorectal cancers, we need more convenient and less invasive screening tests. An infrequently used type of fecal sampling test, which has had Federal Drug Administration approval since 2001, may meet that need he says.

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"In recent years, use of non-invasive screening has declined in favor of colonoscopy, but not everyone is willing to have a colonoscopy," said Dr. Imperiale, who is an IU School of Medicine professor of medicine. "The new immunochemical fecal occult blood test, referred to as I-FOBT, is a significant improvement over the older guaiac-based version. The newer fecal test has the potential to substantially increase screening rates for colorectal cancer, taking us back to the future in a sense." said Dr. Imperiale.

Unlike traditional fecal sampling tests which do not differentiate between blood from diet and blood from the digestive tract, I-FOBT uses antibodies to detect human blood in stool. This increased test specificity eliminates the need for dietary restrictions before colon cancer screening which may induce some individuals who are otherwise unwilling to take a screening test to do so.

Perhaps more importantly, the ability to choose different thresholds to indicate a positive result makes I-FOBT a test that can be used for individuals of any risk. "The test output (amount of hemoglobin per gram of stool) is a continuous variable, which means that a clinician can choose an I-FOBT positivity threshold to suit the patient