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We would concur with Elmunzer et al's findings, based on our own recently published systematic review and meta-analysis on the same topic (DOI: 10.1002/bjs.8882). We reported a 29% relative risk reduction for colorectal cancer (CRC) mortality after flexible sigmoidoscopy (FS) screening compared to no screening (RR 0.71 95%CI 0.61, 0.81).
Elmunzer et al (2012) conclude that "additional comparative effectiveness research of FS...and stool-based testing is necessary to determine the most clinically and cost-effective CRC screening modality." While we reported FS to be superior to faecal occult blood testing (FOBT) at detecting prevalent advanced adenoma and CRC, we were unable to report FS to be superior to faecal immunochemical testing (FIT) at detecting prevalent CRC (RR 1·63 95%CI 0·67, 3·97). The comparative effectiveness of FS compared to FIT in relation to CRC mortality remains unknown. Given that we also found evidence of patient preference for stool-based tests (uptake of FS tends to be lower), the comparative effectiveness of FS compared to FIT needs to be answered so that patients can be fully informed of the implications of their test preferences.