Survival of patients with colorectal cancer detected by a community screening program

Objective: To determine survival rates for people with colorectal cancer de tected through Bowelscan, a community screening program. Design: Survey of data from local medical practitioners, and comparison wit h data from State cancer registries. Subjects and setting: 249 people with colorectal cancer detected after faec al occult blood screening in north-eastern New South Wales, 1987-1996. Foll ow-up was in 1998-1999. Main outcome measures: Five-year survival rates and relative survival ratio s. Results: Five-year survival rates for the screen-detected cancer patients w ere 90% for those with Dukes' stage A cancers, 75% for Dukes' B, 52% for Du kes' C and 0 for Dukes' D (although one person with Dukes' D cancer was liv ing at four-year follow-up at the end of the study). Because of the higher percentage of Dukes' A cases in the population whose cancer was detected th rough screening, the resulting five-year relative survival ratio was signif icantly better than for those recorded by New South Wales, South Australian and Queensland cancer registries: 0.82 (95% confidence interval, 0.74-0.90 ) compared to 0.59 (P less than or equal to 0.001). Conclusions: The study supports the findings of three overseas randomised t rials that screening reduces mortality from colorectal cancer. We estimate that screening 200 000 people would detect about 250 colorectal cancers and prevent as many as 55 deaths.