New Test for Colon Cancer Screening Approved

Colon Cancer RibbonThe Cologuard test is the first DNA based screening test for colorectal cancer that has received approval for use from the FDA and preliminary approval by Medicare to cover the cost of the test. The test detects hemoglobin ( a component of red blood cells) and abnormal DNA in cells picked up by stool . A positive test indicates a need for colonoscopy to identify or eliminate colon cancer as a possibility. We currently screen patients with the fecal occult blood slide test and the more sophisticated fecal immunochemical test or FIT. The new Cologuard detected 92% of colon cancers and 42% of advanced adenomatous colon polyps as compared with 74% and 24 % for FIT. While the Cologuard test was accurate in picking up more colon cancers than the FIT it had slightly more false positive tests than the traditional Fecal Occult Blood Slide.

The Center for Medicare Services ( CMS) is proposing allowing coverage of the DNA test once every three years for beneficiaries who are 50 – 85 years old, asymptomatic and have average risk of colorectal cancer. The new test adds another non-invasive means of screening for colon cancer. We will need to see the cost of the test to the individual patient and accumulate more data on its accuracy in the near future before it becomes a mainstay of colon cancer screening.

At the same time that Cologuard was approved, researchers at the University of Michigan in Ann Arbor published in the online journal Cancer Prevention Research, information showing that evaluation of the pattern of bacteria in the colon of patients improved performance and detection of colon cancer by more than 50% as compared to the Fecal Occult Blood Test alone. Researchers using DNA sequencing and polymerase chain reaction methods were able to identify distinctly different patterns of bacteria in colon cancer and pre-cancerous polyps than in patients with no colon lesions.

It is clear that as researchers apply DNA technology to cancer screening their ability to detect abnormalities and avoid invasive colorectal screening will improve. At the moment recommendations for screening colonoscopy at age 50 remain but as science moves forward that too may soon change.

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