In the United States, a panel of the Food and Drug Administration has endorsed a new colon cancer testing procedure. The test uses DNA from a stool sample to look for precancerous growths and colon cancer.
The FDA panel voted unanimously to endorse the testing procedure which is alternative to the invasive colonoscopy examination. The test is called “Cologard”, and was developed by Exact Sciences, an American company from Wisconsin. The FDA does not have to follow the boards advice, but it is usually the case.
The CEO of Exact Sciences, Kenvin Conry, said: “We are pleased the committee strongly supported Cologuard’s approval. We look forward to continuing our work with the FDA to complete its review of Cologuard and remain committed to addressing the growing unmet needs in colorectal cancer screening.”
Stool tests have been used in the past, with doctors simply looking for hidden blood as a sign that precancerous polyps and tumors may be present in the colon. However this new test uses DNA to obtain a very accurate indication of the presence of polyps and tumors.
The test isn’t 100% effective however. According to recent research in the New England Journal of Medicine, Cologard was 92% effective for spotting colon cancer and 94% effective for spotting early stage colon cancer (stage I and II).
The test looks for altered DNA that is shed during digestion of food. Small genetic changes occur when cancer cells are present in the colon and the test can spot them most of the time.
There are other non-invasive tests that may soon be available as well. The Epi proColon kit from Epigenomics tests blood samples to look for signs of cancer.
Cologard may not be available for a few years however, because follow up studies may be required to further determine the accuracy of the test. Currently the government recommends that patients between the ages of 50 and 75 have annual blood tests done on their stools, however many people don’t do that despite the test only costing $25. We don’t know how much the Cologard test would cost, but presumably it would be more expensive because of it’s additional complexity.
One problem with Cologard is that it does return more false positives, according to researchers. That means it sometimes reported growths where there weren’t any. Doctors also have no idea where the growth is in the colon, so the false positive must be backed up with a colonscopy.
Colorectal cancer is one of the biggest killers in the United States with more than 50’000 people dying annually from the disease. The sad part is that death from this form of cancer is usually avoidable with regular screening. The death rate from colon cancer is decreasing because of greater public awareness, but it is still shockingly high. The key point here is that people need to be screened annually.
Hopefully Cologard will provide an accurate way to determine the presence of the disease without the need for the invasive Colonoscopy that deters many people.