Oral anticoagulants, NSAIDs don't appear to affect FIT accuracy

The accuracy of fecal immunochemical testing (FIT) for colorectal cancer screening does not appear to be affected by use of oral anticoagulants or aspirin/NSAIDs, according to a recent study.

Researchers in the Netherlands performed a systematic review and meta-analysis of studies that compared FIT results in patients at average risk for colorectal cancer who were taking oral anticoagulants or aspirin/NSAIDs versus those who were not taking the drugs. The primary outcome was the pooled positive predictive value of FIT for advanced neoplasia. The results were published online June 5 by Gut.

Eight studies involving 3,563 patients with a positive FIT result were included in the meta-analysis. Seven studies were done in Europe, and one was done in Asia. The positive predictive value of FIT for advanced neoplasia was 37.6% for 633 patients who were taking oral anticoagulants versus 40.3% for 2,930 patients who were not (P=0.75). For 463 patients taking aspirin/NSAIDs, the pooled positive predictive value was 38.2% versus 39.4% in 2,438 patients not taking these drugs (P=0.59).

The authors noted that the cutoff points used for FIT were relatively low overall and that they could not perform subgroup analyses by age, gender, drug type, or therapy duration because the number of included studies was small. They concluded that based on their findings, use of oral anticoagulants and NSAIDs does not affect the positive predictive value of FIT in colorectal cancer screening and that withdrawing the drugs before FIT is not recommended. “However, subgroup analyses on subject and drug characteristics should be performed in order to conduct specific guideline recommendations, and [positivity rate] of FIT in relation to the [positive predictive value] should be taken into account,” the authors wrote.