Colonoscopy findings after increasing two‐stool faecal immunochemical test (FIT) cut‐off: Cross‐sectional analysis of the SCREESCO randomized trial

Abstract

AbstractBackgroundWe determined the impact of an increased two‐stool faecal immunochemical test (FIT) cut‐off on colonoscopy positivity and relative sensitivity and specificity in the randomized controlled screening trial screening of Swedish colons conducted in Sweden.MethodsWe performed a cross‐sectional analysis of participants in the FIT arm that performed FIT between March 2014 and 2020 within the study registered with ClinicalTrials.gov, NCT02078804, who had a faecal haemoglobin concentration of at least 10 µg/g in at least one of two stool samples and who underwent a colonoscopy (n = 3841). For each increase in cut‐off, we computed the positive predictive value (PPV), numbers needed to scope (NNS), sensitivity and specificity for finding colorectal cancer (CRC) and advanced neoplasia (AN; advanced adenoma or CRC) relative to cut‐off 10 µg/g.ResultsThe PPV for AN increased from 23.0% (95% confidence intervals [CI]: 22.3%–23.6%) at cut‐off 10 µg/g to 28.8% (95% CI: 27.8%–29.7%) and 33.1% (95% CI: 31.9%–34.4%) at cut‐offs 20 and 40 µg/g, respectively, whereas the NNS to find a CRC correspondingly decreased from 41 to 27 and 19. The PPV for AN was higher in men than women at each cut‐off, for example 31.5% (95% CI: 30.1%–32.8%) in men and 25.6% (95% CI: 24.3%–27.0%) in women at 20 µg/g. The relative sensitivity and relative specificity were similar in men and women at each cut‐off.ConclusionA low cut‐off of around 20–40 µg/g allows detection and removal of many AN compared to 10 µg/g while reducing the number of colonoscopies in both men and women.