Multitarget stool DNA testing for colorectal-cancer screening.

To the Editor: Imperiale and colleagues evaluate the use of a single-application multitarget stool DNA test for colorectal-cancer screening and compare its performance characteristics with those of the FIT. Two important points warrant further discussion. First, the investigators used a FIT cutoff value of 100 ng of hemoglobin per milliliter of buffer (equivalent to 20 μg of hemoglobin per gram of feces)1 instead of a lower cutoff value; this may explain the decreased sensitivity of FIT (73.8%) for colorectal cancer in their study. Recently, our systematic review and meta-analysis showed that FITs with a cutoff value of less than 20 μg per gram had a sensitivity of 89% and a specificity of 91% for colorectal cancer in an asymptomatic, average-risk population.2 Second, the overall positive rate for the stool DNA test was higher (16.1%) than that of the FIT (7.0%); this was mainly due to the higher false positive rate for the stool DNA test. This finding is an important issue to consider given the unclear screening interval for stool DNA testing and the lack of colonoscopy resources across the world.

0