乳腺癌筛查能否减少老年人死亡风险
众所周知，乳腺癌或前列腺癌筛查与未筛查相比，大约10年后，癌症死亡风险和全因死亡风险显著较低，因此指南不推荐对预计寿命不足10年的老年人常规进行乳腺癌或前列腺癌筛查。不过，医疗保险索赔预后指数研究表明，是否同意癌症筛查本身与死亡风险密切相关，这表明该指数用于癌症筛查知情告知时可能将个别人错误分类，由于该指数未考虑合并症和体力状态，故该结果可能归咎于其他影响因素。
2021年6月1日，《美国医学会杂志》网络开放版在线发表霍普金斯大学、圣伊丽莎白扬斯敦医院、加利福尼亚大学旧金山医学院的研究报告，考虑了合并症和体力状态后，分析了癌症筛查是否仍与老年人10年全因死亡风险显著相关。
该队列研究于2020年1月～11月对符合乳腺癌或前列腺癌筛查资格参加2004年健康与退休研究的年龄大于65岁老年人及其2001年～2015年医疗保险索赔数据进行回顾分析。通过多因素比例风险回归模型，对年龄、性别、合并症和体力状态等预后指数进行校正后，分析10年全因死亡风险与乳腺钼靶筛查或前列腺特异性抗原检测的相关性，还检测了癌症筛查与死亡风险相关性的可能影响因素（学历、收入、婚姻、地理、认知能力、自我报告健康、自我保健、自我感知死亡风险）。
结果，乳腺癌筛查队列包括3257例女性（平均年龄77.8±7.5岁），前列腺癌筛查队列包括2085例男性（平均年龄76.1±6.8岁）。
对全部预后指数进行校正后：
乳腺钼靶筛查与未筛查相比：全因死亡风险低33%，仍然具有统计学意义（校正后风险比：0.67，95%置信区间：0.60～0.74）
前列腺癌筛查与未筛查相比：全因死亡风险低12%，仍然具有统计学意义（校正后风险比：0.88，95%置信区间：0.78～0.99）
其他可能影响因素都未削弱筛查与死亡风险的相关性，除了认知能力：
乳腺钼靶筛查与未筛查相比：全因死亡风险低30%，仍然具有统计学意义（校正后风险比：0.7，95%置信区间：0.64～0.82）
前列腺癌筛查与未筛查相比：全因死亡风险低10%，不再具有统计学意义（校正后风险比：0.9，95%置信区间：0.80～1.05）
因此，该研究结果表明，认知能力可削弱癌症筛查与老年人死亡风险之间的相关性，现有死亡风险预测算法可能缺少癌症筛查与长期死亡风险相关性的重要指标。仅仅依靠算法决定是否癌症筛查，可能将个别人错误分类为预计寿命有限并过早停止筛查。筛查决策需要个体化，而非仅仅依靠预计寿命预测。
JAMA Netw Open. 2021 Jun 1;4(6):e2112062.
Association Between Receipt of Cancer Screening and All-Cause Mortality in Older Adults.
Nancy L. Schoenborn, Orla C. Sheehan, David L. Roth, Tansu Cidav, Jin Huang, Shang-En Chung, Talan Zhang, Sei Lee, Qian-Li Xue, Cynthia M. Boyd.
The Johns Hopkins University School of Medicine, Baltimore, Maryland; The Johns Hopkins Center on Aging and Health, Baltimore, Maryland; Bon Secours Mercy Health St Elizabeth Youngstown Hospital, Youngstown, Ohio; University of California, San Francisco School of Medicine.
This cohort study examines whether cancer screening is significantly associated with all-cause mortality in older adults after accounting for comorbidities and functional status.
QUESTION: Is receipt of cancer screening independently associated with 10-year mortality after accounting for comorbidities and function in older adults?
FINDINGS: In this cohort study of 5342 patients in the Health and Retirement Study, receipt of breast or prostate cancer screening was associated with a lower hazard of 10-year mortality after adjusting for all variables from a prognostic index that included age, comorbidities, and function.
MEANING: These findings suggest that screening decisions need to be individualized and not solely dependent on mortality prediction.
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.
DOI: 10.1001/jamanetworkopen.2021.12062