Screening Sigmoidoscopy reduces colorectal cancer mortality.

In clinical trial conducted by NCI, From 1993 through 2001, randomly assigned 154,900 men and women 55 to 74 years of age either to screening with flexible sigmoidoscopy, to usual care. The incidence of colorectal cancer after a median follow-up of 11.9 years was 11.9 cases per 10,000 person-years in the intervention group (1012 cases), as compared with 15.2 cases per 10,000 person-years in the usual-care group (1287 cases), which represents a 21% reduction .Significant reductions were observed in the incidence of both distal an proximal colorectal cancers .Mortality from distal colorectal cancer was reduced by 50% .Mortality from proximal colorectal cancer was unaffected In short,screening with flexible sigmoidoscopy was associated with a significant decrease in colorectal-cancer incidence (in both the distal and proximal colon) and mortality (distal colon only).