Comparative Effectiveness of Fecal Immunochemical Tests versus Flexible Sigmoidoscopy for Colorectal Cancer Screening: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.

Background And Aims: Fecal immunochemical tests (FITs) and flexible sigmoidoscopies are commonly used modalities for colorectal cancer (CRC) screening. We performed a systematic review and meta-analysis to compare the effectiveness of FIT and sigmoidoscopy in CRC screening.

Methods: PRISMA statement and Cochrane guidelines were followed for this review. Digital dissertation databases were searched from inception till December 1st 2020 and randomized clinical trials comparing the detection rates of CRC for FIT and sigmoidoscopy were included. Outcomes for analysis included participation rates and detection rates of CRC, advanced adenomas and advanced colorectal neoplasia for both screening modalities.

Results: Five randomized clinical trials with a total of 261,755 patients were included for the analysis. The participation rate for FIT was significantly higher compared to flexible sigmoidoscopy (OR 2.11, 95% CI 1.29-3.44, p=0.003). In intention-to-screen analysis, the detection rate for advanced colorectal neoplasia was significantly lower with FIT (OR 0.62, 95% CI 0.45-0.84, p=0.002) as compared to flexible sigmoidoscopy but not statistically different for CRC (OR 1.15, 95% CI 0.65-2.02, p=0.63).

Conclusion: Despite lower participation amongst patients, CRC screening with flexible sigmoidoscopy leads to higher detection of advanced colorectal neoplasia, when compared to a single round of fecal immunochemical testing.