乳腺癌筛查

Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.

Am J Surg. 1999 Jun;177(6):518-24. doi: 10.1016/s0002-9610(99)00096-3.

PURPOSE AND DESIGN

Three breast cancer screening methods are commonly employed: mammography, breast self examination (BSE), and physical examination by trained personnel (PE). Case-control, retrospective, and prospective studies have examined the efficacy of these screening modalities in reducing breast cancer mortality. However, there are three biases pertinent to many of these studies: lead-time, length, and selection biases. The best way to exclude these biases is to compare screened and unscreened women in a randomized controlled trial with breast cancer mortality as the end point. Eight trials have examined the effect of mammographic screening on breast cancer mortality and two have examined the impact of screening with BSE. In addition, a large trial will soon be initiated in India to assess the impact of screening by PE on breast cancer mortality. This article reviews these trials and discusses the implications of the studies.

RESULTS

The overall results of the randomized controlled trials indicate that mammographic screening in women over age 50 can reduce breast cancer mortality by about 25%. However, its efficacy in women between the ages of 40 and 49 is disputed, and another large trial has been initiated in the United Kingdom to resolve this controversy. Preliminary results of two trials indicate that BSE has no impact on breast cancer mortality. However, longer follow-up of these trials is necessary before drawing any conclusions regarding BSE.

CONCLUSIONS

Mammographic screening in postmenopausal women is an effective means of reducing breast cancer mortality. However, the impact of mammographic screening on breast cancer mortality in premenopausal women is disputed. At least four potentially harmful consequences of mammographic screening merit consideration: lead time effect, radiation exposure, false-positives, and overdiagnosis. Thus, women between the ages of 40 and 49, in particular, should be informed of the potential for benefit and harm prior to mammographic screening.

目的与设计

常用的三种乳腺癌筛查方法为：乳房X线摄影、乳房自我检查（BSE）以及由专业人员进行的体格检查（PE）。病例对照研究、回顾性研究和前瞻性研究均已检验了这些筛查方式在降低乳腺癌死亡率方面的效果。然而，许多此类研究存在三种偏差：领先时间偏差、病程长度偏差和选择偏差。排除这些偏差的最佳方法是在以乳腺癌死亡率为终点的随机对照试验中比较接受筛查和未接受筛查的女性。八项试验检验了乳房X线摄影筛查对乳腺癌死亡率的影响，两项试验检验了BSE筛查的影响。此外，印度即将启动一项大型试验，以评估PE筛查对乳腺癌死亡率的影响。本文回顾了这些试验并讨论了研究的意义。

结果

随机对照试验的总体结果表明，50岁以上女性进行乳房X线摄影筛查可使乳腺癌死亡率降低约25%。然而，其在40至49岁女性中的效果存在争议，英国已启动另一项大型试验以解决这一争议。两项试验的初步结果表明，BSE对乳腺癌死亡率没有影响。然而，在就BSE得出任何结论之前，有必要对这些试验进行更长时间的随访。

结论

绝经后女性进行乳房X线摄影筛查是降低乳腺癌死亡率的有效手段。然而，乳房X线摄影筛查对绝经前女性乳腺癌死亡率的影响存在争议。乳房X线摄影筛查至少有四个潜在有害后果值得考虑：领先时间效应、辐射暴露、假阳性结果和过度诊断。因此，尤其对于40至49岁的女性，在进行乳房X线摄影筛查之前，应告知其潜在的益处和危害。