Fecal Immunochemical Testing for Colorectal Cancer Screening Outside High-income Countries: A Systematic Review and Meta-Analysis.

Goal: Investigate fecal immunochemical testing (FIT) for CRC screening outside high-income countries (HIC).

Background: Colorectal cancer (CRC) incidence in low- and middle-income countries (LMIC) is rising, but optimal screening strategies in resource-limited settings remain unclear. FIT is an evidence-based, low-cost modality for population-based CRC screening. We performed a systematic review with meta-analysis to better understand the diagnostic performance of FIT for detecting CRC among average-risk individuals living outside HICs.

Study: A systematic search of studies conducted in LMICs, defined by the World Bank, was conducted on August 8, 2024. Studies were eligible if they assessed FIT as a diagnostic test for CRC in asymptomatic, average-risk participants. Pooled estimates for FIT sensitivity and specificity were calculated using a bivariate Bayesian statistical analysis (MetaBayesDTA).

Results: Our search returned 333 distinct studies. Of these, 263 were excluded after title and abstract screening. We reviewed 61 full texts with 7 meeting inclusion/exclusion criteria. These studies were published between 2015 and 2022 and included 100,619 participants from Argentina, Brazil, China, Iran, and Thailand. Most used a FIT hemoglobin cutoff of 50 ng/mL (n=4). FIT return rate ranged from 78% to 99%, and positivity ranged from 2.1% to 29%. FIT sensitivity ranged from 55% to 92%, specificity from 71% to 94%, PPV from 2% to 16%, and NPV from 98% to 100%. After meta-analysis, pooled estimates for sensitivity and specificity for CRC were 75% (95% CI: 64%-85%) and 89% (95% CI: 77%-95%), respectively.

Conclusions: FIT-based CRC screening shows promise, but data was geographically limited to middle-income countries. This highlights the need for research evaluating screening modalities and completion of the screening continuum in LMICs.