Effect of Three Decades of Screening Mammography on Breast-Cancer Incidence
Effect of Three Decades of Screening Mammography on Breast-Cancer Incidence
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DOI：
10.1056/nejmoa1206809
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发表时间：
2012-11-22
影响因子：
158.5
通讯作者：
Welch, H. Gilbert
中科院分区：
文献类型：
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作者：
Bleyer, Archie;Welch, H. Gilbert
为了降低死亡率，筛查必须在更早、更可治愈的阶段发现危及生命的疾病。因此，有效的癌症筛查计划既增加了早期发现的癌症发病率，又减少了晚期癌症的发病率。和最终结果数据，以检查1976年至2008年早期乳腺癌发病率的趋势（导管原位癌和局限性疾病）和晚期乳腺癌（区域和远处疾病）在40岁或以上的妇女中。结果在美国引入筛查性乳房X光检查与早期乳腺癌病例数量的增加有关，从2004年到2005年，每年发现的第三期乳腺癌病例从每100 000名妇女112例增加到234例，绝对增加了每100 000名妇女122例。与此同时，晚期癌症妇女的发病率下降了8%，从每100 000名妇女102例下降到94例-每100 000名妇女绝对减少了8例。在假设基础疾病负担不变的情况下，在122例额外诊断的早期癌症中，预计只有8例进展为晚期疾病。在排除了与乳腺癌替代治疗相关的短暂过度发病率并调整了40岁以下女性乳腺癌发病率的趋势后，我们估计乳腺癌被过度诊断（即，在过去的30年里，有130万美国妇女在筛查中发现了肿瘤，而这些肿瘤绝不会导致临床症状。我们估计，在2008年，乳腺癌被过度诊断超过70，000名妇女，这占31%的所有乳腺癌diagnosed. ConclusionsSubstantially增加的情况下，早期乳腺癌的检测，筛查乳房X光检查只有轻微降低妇女目前与晚期癌症的比率。虽然不确定哪些妇女受到影响，但这种不平衡表明存在大量过度诊断，占所有新诊断的乳腺癌的近三分之一，而且筛查充其量只能对乳腺癌死亡率产生很小的影响。
BackgroundTo reduce mortality, screening must detect life-threatening disease at an earlier, more curable stage. Effective cancer-screening programs therefore both increase the incidence of cancer detected at an early stage and decrease the incidence of cancer presenting at a late stage.MethodsWe used Surveillance, Epidemiology, and End Results data to examine trends from 1976 through 2008 in the incidence of early-stage breast cancer (ductal carcinoma in situ and localized disease) and late-stage breast cancer (regional and distant disease) among women 40 years of age or older.ResultsThe introduction of screening mammography in the United States has been associated with a doubling in the number of cases of early-stage breast cancer that are detected each year, from 112 to 234 cases per 100,000 women - an absolute increase of 122 cases per 100,000 women. Concomitantly, the rate at which women present with late-stage cancer has decreased by 8%, from 102 to 94 cases per 100,000 women - an absolute decrease of 8 cases per 100,000 women. With the assumption of a constant underlying disease burden, only 8 of the 122 additional early-stage cancers diagnosed were expected to progress to advanced disease. After excluding the transient excess incidence associated with hormone-replacement therapy and adjusting for trends in the incidence of breast cancer among women younger than 40 years of age, we estimated that breast cancer was overdiagnosed (i.e., tumors were detected on screening that would never have led to clinical symptoms) in 1.3 million U.S. women in the past 30 years. We estimated that in 2008, breast cancer was overdiagnosed in more than 70,000 women; this accounted for 31% of all breast cancers diagnosed.ConclusionsDespite substantial increases in the number of cases of early-stage breast cancer detected, screening mammography has only marginally reduced the rate at which women present with advanced cancer. Although it is not certain which women have been affected, the imbalance suggests that there is substantial overdiagnosis, accounting for nearly a third of all newly diagnosed breast cancers, and that screening is having, at best, only a small effect on the rate of death from breast cancer.