Survival benefit for patients with colorectal cancer detected by population-based screening program using an immunochemical fecal occult blood test.

The effectiveness of screening for colorectal cancer by an immunochemical fecal occult blood test was investigated by comparing the survival time of 194 screen-detected colorectal cancer subjects (screen-detected group) with that of 352 routinely diagnosed subjects (control group). The rate of Dukes' A cancers was significantly higher in screen-detected group than in the control group (43.8% vs 16.8%, p<0.0001), whereas that of Dukes' D cancer was the opposite (5.7% vs 21.3%, p<0.0001). The survival rate for screen-detected group was higher than that for the control group (Kaplan-Meier method, p<0.0001). By a proportional hazard model with adjustment for prognostic factors except stage, the risk ratio of death from colorectal cancer was 0.40 (p=0.0007) for screen-detected group versus the control group. Therefore, the screening was suggested to be effective in survival benefit, although there might be potential biases inherent in observational studies.