Risk of colorectal cancer and colorectal cancer mortality beginning one year after a negative fecal occult blood test, among screen-eligible 76-85-year-olds

Colorectal cancer (CRC) screening is universally recommended for adults ages 45-75 years. Noninvasive fecal occult blood tests are effective screening tests recommended by guidelines. However, empirical evidence to inform older adults’ decisions about whether to continue screening is sparse, especially for individuals with prior screening. This study used a retrospective cohort of older adults at three Kaiser Permanente integrated healthcare systems (Northern California, Southern California, Washington) and Parkland Health (Dallas, Texas). Beginning one year following a negative stool-based screening test, cumulative risks of CRC incidence, CRC mortality (accounting for deaths from other causes), and non-CRC mortality were estimated. Cumulative incidence of CRC in screen-eligible adults aged 76-85 with a negative fecal occult blood test one year ago (N=118,269) was 0.23% (95% confidence interval [CI]: 0.20-0.26%) after two years and 1.21% (95% CI:1.13-1.30%) after eight years. Cumulative CRC mortality was 0.03% (95% CI: 0.02-0.04%) after two years and 0.33% (95% CI: 0.28-0.39%) after eight years. Cumulative risk of death from non-CRC causes was 4.81% (95% CI: 4.68-4.96%) after two years and 28.40% (95% CI: 27.95-28.85%) after eight years. Among 76-85 year-olds with a recent negative stool-based test, cumulative CRC incidence and mortality estimates were low, especially within two years; death from other causes was over 100 times more likely than death from CRC. These findings of low absolute CRC risk, and comparatively higher risk of death from other causes, can inform decision-making regarding whether and when to continue CRC screening beyond age 75 among screen-eligible adults.

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