New Stool Tests for Colon Cancer

Just a couple of days ago I summarized the new recommendations for screening for colorectal cancer – scroll down the page to see the post. They included the use of fecal occult blood testing (FOBT), a test for blood in the stool, that has served well over he years as a preliminary warning. The use of stool DNA testing was introduced a year or two ago, but it failed to prove superior to FOBT in predicting the presence of colorectal cancer. A new DNA test system – the second generation, if you like – has been developed, and its performance is described in an article in the Annals of Internal Medicine.

Over 3,750 healthy adults provided 3 stool samples, which were tested at 2 central labs. FOBT was estimated using two methods, and DNA tests – the original one and the newer one – were done at the second lab. All the volunteers had a colonoscopy, the most reliable test for colon polyps and cancer.

The better of the two tests for blood in the stool detected 21% of the cases of cancer and most of the suspicious polyps. The original DNA test detected 20% of the cases of cancer. But the new DNA test found 40% of the cases of cancer and suspicious polyps.

This study suggests that the newer DNA testing method is a considerable improvement over the existing FOBT and DNA tests. It will take sometime before it can be approved by the FDA and made available to all, but it’s a step forward towards improved screening without colonoscopy.