Miller EA, et al. - In this investigation, researchers assessed the effectiveness of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality. Study participants in the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) trial were selected from the general population in the catchment areas of ten screening centers across the United States; they did not currently have or have a history of prostate, lung, colorectal, or ovarian cancer, and were not receiving cancer treatment. Participants (aged 55–74 years) were randomly assigned to usual care or flexible sigmoidoscopy at baseline and again at 3 years or 5 years from 1993 to 2001. They observed that the mortality reduction was limited to the distal colon without significant effect in the proximal colon. Incidence reductions were significantly higher in men than in women, and mortality reductions were significantly higher in the older age group. Findings revealed that reductions in the incidence and mortality of colorectal cancer from flexible sigmoidoscopy screening are sustained over the long term.