Regular use of aspirin and direct-acting oral anticoagulants (DOACs) can interfere with fecal immunochemical tests (FIT) for colorectal cancer (CRC), increasing the risk of false positives, according to a study published in Gastroenterology.
Researchers conducted a cross-sectional study in an ongoing CRC screening trial in Norway. They included 4,908 patients 50 to 74 years with a positive result from a FIT (defined as >15 μg hemoglobin/g feces) who underwent subsequent colonoscopy. They categorized patients as “users” who regularly used aspirin (n=1,008), warfarin (n=147), or DOACs (n=212). These patients were matched to non-users (n=3,541) based on age, sex, screening center, and screening round.
Effects of Oral Anticoagulants and Aspirin on Performance of Fecal Immunochemical Tests in Colorectal Cancer Screening – https://t.co/trh1k95hMG
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During the study, CRC was diagnosed in 234 individuals and advanced adenomas were diagnosed in 1,305 individuals. The positive predictive value (PPV) for CRC was 3.8% for aspirin users compared with 6.4% for matched non-users (P=0.006). The PPV for advanced adenoma was 27.2% and 32.6%, respectively (P=0.011).
The PPV for CRC was 0.9% in DOAC users versus 6.8% in matched non-users (P=0.001). The PPV for advanced adenoma was 20.5% and 32.4%, respectively (P=0.002).
There was no significant difference in PPVs for CRC or advanced adenoma in warfarin users compared to non-users.