过度诊断被越来越多地认识到是乳腺癌筛查的一种危害，尤其是对于年长妇女而言。本研究旨在通过年龄评估乳腺癌筛查对年长妇女的过度诊断情况。采用回顾性队列研究方法，将继续在下一个间隔期内接受筛查的年长妇女与不接受筛查的妇女进行乳腺癌累积发病率比较。分析采用竞争风险模型，以年龄分层。数据来源于按次收费的医疗保险索赔资料与SEER（监测、流行病学和终点）计划进行关联。对象为最近接受筛查的70岁及以上的妇女。对乳腺癌的诊断结果及随访期内的乳腺癌死亡结果进行研究，随访期为15年。研究共包括54635名妇女。70至74岁的妇女中，筛查妇女的乳腺癌调整后累积发病率为每100名筛查妇女6.1例（95% CI 5.7至6.4），与未接受筛查妇女的每100名发病率4.2例（CI 3.5至5.0）相比。据估计，接受筛查的妇女中约有31%的乳腺癌可能是过度诊断的。对于75至84岁的妇女，筛查妇女的累积发病率为每100名筛查妇女4.9例（CI 4.6至5.2），与未接受筛查妇女的每100名发病率2.6例（CI 2.2至3.0）相比，其中约有47%的病例可能是过度诊断的。对于85岁及以上的妇女，筛查妇女的累积发病率为每100名筛查妇女2.8例（CI 2.3至3.4），未接受筛查的妇女为每100名发病率1.3例（CI 0.9至1.9），过度诊断率高达54%。我们未观察到与筛查相关的乳腺癌特异性死亡显著减少。本研究仅旨在评估过度诊断的情况，限制了我们对筛查的所有益处与危害作出结论的能力。筛查妇女之间在乳腺癌风险和竞争性死亡方面的未测量差异可能会对结果造成混淆。结果对模型规范和筛查乳腺X线检查定义敏感。继续进行乳腺癌筛查与乳腺癌发病率增加相关，这表明年长妇女在筛查后被诊断为乳腺癌的过度诊断可能很常见。过度诊断的危害是否可以与益处相抵消，以及对谁而言更为重要，是一个重要的问题。 国家癌症研究所。

Overdiagnosis is increasingly recognized as a harm of breast cancer screening, particularly for older women.To estimate overdiagnosis associated with breast cancer screening among older women by age.Retrospective cohort study comparing the cumulative incidence of breast cancer among older women who continued screening in the next interval with those who did not. Analyses used competing risk models, stratified by age.Fee-for-service Medicare claims, linked to the SEER (Surveillance, Epidemiology, and End Results) program.Women 70 years and older who had been recently screened.Breast cancer diagnoses and breast cancer death for up to 15 years of follow-up.This study included 54 635 women. Among women aged 70 to 74 years, the adjusted cumulative incidence of breast cancer was 6.1 cases (95% CI, 5.7 to 6.4) per 100 screened women versus 4.2 cases (CI, 3.5 to 5.0) per 100 unscreened women. An estimated 31% of breast cancer among screened women were potentially overdiagnosed. For women aged 75 to 84 years, cumulative incidence was 4.9 (CI, 4.6 to 5.2) per 100 screened women versus 2.6 (CI, 2.2 to 3.0) per 100 unscreened women, with 47% of cases potentially overdiagnosed. For women aged 85 and older, the cumulative incidence was 2.8 (CI, 2.3 to 3.4) among screened women versus 1.3 (CI, 0.9 to 1.9) among those not, with up to 54% overdiagnosis. We did not see statistically significant reductions in breast cancer-specific death associated with screening.This study was designed to estimate overdiagnosis, limiting our ability to draw conclusions on all benefits and harms of screening. Unmeasured differences in risk for breast cancer and differential competing mortality between screened and unscreened women may confound results. Results were sensitive to model specifications and definition of a screening mammogram.Continued breast cancer screening was associated with greater incidence of breast cancer, suggesting overdiagnosis may be common among older women who are diagnosed with breast cancer after screening. Whether harms of overdiagnosis are balanced by benefits and for whom remains an important question.National Cancer Institute.