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

J Intern Med. 2024 Aug;296(2):187-199. doi: 10.1111/joim.13810. Epub 2024 Jun 6.

Abstract

Background: We 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.

Methods: We 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.

Results: The 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.

Conclusion: A 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.

Keywords: colonoscopy; colorectal cancer; faecal immunochemical test; screening.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adenoma / diagnosis
  • Aged
  • Colonoscopy*
  • Colorectal Neoplasms* / diagnosis
  • Cross-Sectional Studies
  • Early Detection of Cancer* / methods
  • Feces / chemistry
  • Female
  • Hemoglobins / analysis
  • Humans
  • Immunochemistry
  • Male
  • Middle Aged
  • Occult Blood*
  • Predictive Value of Tests
  • Sensitivity and Specificity*
  • Sweden

Substances

  • Hemoglobins

Associated data

  • ClinicalTrials.gov/NCT02078804