Association Between Receipt of Cancer Screening and All-Cause Mortality in Older Adults.

Importance: Guidelines recommend against routine breast and prostate cancer screenings in older adults with less than 10 years' life expectancy. One study using a claims-based prognostic index showed that receipt of cancer screening itself was associated with lower mortality, suggesting that the index may misclassify individuals when used to inform cancer screening, but this finding was attributed to residual confounding because the index did not account for functional status. Objective: To examine whether cancer screening remains significantly associated with all-cause mortality in older adults after accounting for both comorbidities and functional status. Design, Setting, and Participants: This cohort study included individuals older than 65 years who were eligible for breast or prostate cancer screening and who participated in the 2004 Health and Retirement Study. Data were linked to Medicare claims from 2001 to 2015. Data analysis was conducted from January to November 2020. Main Outcomes and Measures: A Cox model was used to estimate the association between all-cause mortality over 10 years and receipt of screening mammogram or prostate-specific antigen (PSA) test, adjusting for variables in a prognostic index that included age, sex, comorbidities, and functional status. Potential confounders (ie, education, income, marital status, geographic region, cognition, self-reported health, self-care, and self-perceived mortality risk) of the association between cancer screening and mortality were also tested. Results: The breast cancer screening cohort included 3257 women (mean [SD] age, 77.8 [7.5] years); the prostate cancer screening cohort included 2085 men (mean [SD] age, 76.1 [6.8] years). Receipt of screening mammogram was associated with lower hazard of all-cause mortality after accounting for all index variables (adjusted hazard ratio [aHR], 0.67; 95% CI, 0.60-0.74). A weaker, but still statistically significant, association was found for screening PSA (aHR 0.88; 95% CI, 0.78-0.99). None of the potential confounders attenuated the association between screening and mortality except for cognition, which attenuated the aHR for mammogram from 0.67 (95% CI, 0.60-0.74) to 0.73 (95% CI, 0.64-0.82) and the aHR for PSA from 0.88 (95% CI, 0.78-0.99) to 0.92 (95% CI, 0.80-1.05), making PSA screening no longer statistically significant. Conclusions and Relevance: In this study, cognition attenuated the observed association between cancer screening and mortality among older adults. These findings suggest that existing mortality prediction algorithms may be missing important variables that are associated with receipt of cancer screening and long-term mortality. Relying solely on algorithms to determine cancer screening may misclassify individuals as having limited life expectancy and stop screening prematurely. Screening decisions need to be individualized and not solely dependent on life expectancy prediction.