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

Objective To determine survival rates for people with colorectal cancer detected through Bowelscan, a community screening program. Design Survey of data from local medical practitioners, and comparison with data from State cancer registries. Subjects and setting 249 people with colorectal cancer detected after faecal occult blood screening in north‐eastern New South Wales, 1987–1996. Follow‐up was in 1998–1999. Main outcome measures Five‐year survival rates and relative survival ratios. Results Five‐year survival rates for the screen‐detected cancer patients were 90% for those with Dukes' stage A cancers, 75% for Dukes' B, 52% for Dukes' C and 0 for Dukes' D (although one person with Dukes' D cancer was living 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 through screening, the resulting five‐year relative survival ratio was significantly 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 ≤ 0.001). Conclusions The study supports the findings of three overseas randomised trials 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.