Estimating the magnitude of colorectal cancers prevented during the era of screening: 1976 to 2009

Ideally, screening detects cancer at a more curable stage and, as a result, decreases the rate of subsequent diagnosis at a late stage. Although it is suggested that some cancer screening tests have led to substantial increases in early‐stage incidence with only marginal reductions in late‐stage incidence (eg mammography), the association between temporal trends in colorectal cancer screening and its cumulative impact on colorectal cancer incidence is unknown.