中文摘要
有证据表明，乳腺X线摄影会诊断出一些最终不会引发症状的乳腺癌，这一现象被称为“过度诊断”；对此，乳腺X线摄影指南已有所弱化。鉴于对过度诊断的担忧，美国指南不再推荐40—49岁女性接受乳腺X线摄影，而是鼓励她们根据自身情况自行决定是否接受检查。为评估这些指南能否有效地针对目标女性群体，我提出了一种方法，考察一项具有重要影响力的临床试验中的乳腺X线摄影行为；该试验对参与者进行了足够长时间的随访，从而能够发现过度诊断情况。我发现，更有可能接受乳腺X线摄影的女性健康状况更好、社会经济地位更高。更重要的是，我发现，在最有可能接受乳腺X线摄影的女性中，20年期过度诊断水平至少高出3.5倍。她们所患癌症中至少有36%属于过度诊断。这些发现意味着，美国指南鼓励健康状况较好的女性接受乳腺X线摄影，而这些女性更有可能因此遭到过度诊断。其他国家的指南则并非如此。
Abstract
Mammography guidelines have weakened in response to evidence that mammograms diagnose breast cancers that would never eventually cause symptoms, a phenomenon called "overdiagnosis." Given concerns about overdiagnosis, instead of recommending mammograms, US guidelines encourage women aged 40-49 to get them as they see fit. To assess whether these guidelines target women effectively, I propose an approach that examines mammography behavior within an influential clinical trial that followed participants long enough to find overdiagnosis. I find that women who are more likely to receive mammograms are healthier and have higher socioeconomic status. More importantly, I find that the 20-year level of overdiagnosis is at least 3.5 times higher among women who are most likely to receive mammograms. At least 36% of their cancers are overdiagnosed. These findings imply that US guidelines encourage mammograms among healthier women who are more likely to be overdiagnosed by them. Guidelines in other countries do not.