In this issue of JAMA, Holme and colleagues1 report results of a large randomized trial of colorectal cancer screening in Norway in which one-time flexible sigmoidoscopy was compared with no screening. In intention-to-screen analysis—which included all people invited for screening, regardless of their follow-through—relative reductions in colorectal cancer incidence and cancer-specific mortality were 20% and 27% in the sigmoidoscopy group, respectively, compared with the no-screening control group, during an average follow-up of about 11 years. In absolute terms, colorectal cancer death was averted in 1 person per 1000; cancer-specific mortality was roughly 4 per 1000 in the control group and 3 per 1000 in the sigmoidoscopy group. Colorectal cancer mortality curves did not diverge until the ninth year, suggesting that the benefit of screening might increase with longer follow-up. Additionally, because only two-thirds of people invited for screening actually participated, the population benefit would likely be higher with greater adherence. Half the sigmoidoscopy group also received one-time immunological fecal occult blood testing (FOBT), but this addition did not improve outcomes beyond sigmoidoscopy alone.
Brett AS. Flexible Sigmoidoscopy for Colorectal Cancer ScreeningMore Evidence, Persistent Ironies. JAMA. 2014;312(6):601-602. doi:10.1001/jama.2014.8613