Use of Antiplatelet Agents Decreases the Positive Predictive Value of Fecal Immunochemical Tests for Colorectal Cancer but Does Not Affect Their Sensitivity

Abstract

Previous studies have evaluated the effects of antithrombotic agents on the performance of fecal immunochemical tests (FITs) for the detection of colorectal cancer (CRC), but the results were inconsistent and based on small sample sizes. We studied this topic using a large-scale population-based database. Using the Korean National Cancer Screening Program Database, we compared the performance of FITs for CRC detection between users and non-users of antiplatelet agents and warfarin. Non-users were matched according to age and sex. Among 5,426,469 eligible participants, 768,733 used antiplatelet agents (mono/dual/triple therapy, n = 701,683/63,211/3839), and 19,569 used warfarin, while 4,638,167 were non-users. Among antiplatelet agents, aspirin, clopidogrel, and cilostazol ranked first, second, and third, respectively, in terms of prescription rates. Users of antiplatelet agents (3.62% vs. 4.45%; relative risk (RR): 0.83; 95% confidence interval (CI): 0.78–0.88), aspirin (3.66% vs. 4.13%; RR: 0.90; 95% CI: 0.83–0.97), and clopidogrel (3.48% vs. 4.88%; RR: 0.72; 95% CI: 0.61–0.86) had lower positive predictive values (PPVs) for CRC detection than non-users. However, there were no significant differences in PPV between cilostazol vs. non-users and warfarin users vs. non-users. For PPV, the RR (users vs. non-users) for antiplatelet monotherapy was 0.86, while the RRs for dual and triple antiplatelet therapies (excluding cilostazol) were 0.67 and 0.22, respectively. For all antithrombotic agents, the sensitivity for CRC detection was not different between users and non-users. Use of antiplatelet agents, except cilostazol, may increase the false positives without improving the sensitivity of FITs for CRC detection.

The effect of antithrombotic treatment on the fecal immunochemical test for colorectal cancer screening: a nationwide cross-sectional study

“…5 Triple therapy relates to any combination of the treatments above involving three drugs. [16]. The results regarding antiplatelet treatment are similar to our findings; however, the results regarding VKAs do not match the reduction in PPV for CRC found in our study (adjusted RR 0.68 [95 %CI 0.53-0.87]).…”

“…Most recently, in 2021, a population-based Korean study was conducted by Jung et al The authors analyzed more than 5 million participants, of whom 786 733 were receiving antiplatelet treatment and 19 569 were receiving VKAs. Antiplatelet treatment reduced the PPV of FIT (RR 0.83 [95 %CI 0.78–0.88]); however, treatment with VKAs did not (RR 0.92 [95 %CI 0.64–1.34]) 16 . The results regarding antiplatelet treatment are similar to our findings; however, the results regarding VKAs do not match the reduction in PPV for CRC found in our study (adjusted RR 0.68 [95 %CI 0.53–0.87]).…”

“…The Korean study was also limited by not including any patients receiving NOAC treatment, as the study period was from 2009 until 2011 [16].…”

“…One explanation could be the fact that, in the Korean population, treatment with VKA after ischemic stroke only achieves the targeted therapeutic range 44.6 % of the time, with 41.7 % having an international normalized ratio (IVR) < 2.0 [26]; in Denmark, the targeted therapeutic range is achieved 69.3 % of the time [27]. The Korean study was also limited by not including any patients receiving NOAC treatment, as the study period was from 2009 until 2011 [16].…”

“…The impact of antithrombotic treatment on the efficacy of FIT for CRC detection has been sparsely evaluated [11][12][13][14][15][16]. The studies have been limited by a relatively low number of participants and they were most often conducted in an opportunistic screening setting.…”