Re: Canadian national breast screening study-2: 13-year results of a randomized trial in women aged 50-59 years.
Re: Canadian national breast screening study-2: 13-year results of a randomized trial in women aged 50-59 years.
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回复：加拿大国家乳房筛查研究 2：针对 50-59 岁女性的随机试验 13 年结果。
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
S. A. Narod
中科院分区：
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作者：
S. A. Narod
米勒等人（1）报告了加拿大乳腺筛查随机试验的最新结果。随机化后16年，在随机分配接受年度乳房X光检查和体检的女性中，观察到107例死亡，在随机分配接受年度体检的女性中，观察到105例死亡。作者解释说，这意味着这两种筛查方法是等效的，即，每年由受过训练的专业人员进行体检是每年乳房X光检查的一种可行的替代办法，应向50岁或50岁以上的妇女提供。几家媒体在报道试验结果的公布时也强调了这一信息。如果这是一个单独的乳房X光检查与单独的身体检查的试验，这个结论是合理的。然而，如果乳房X线摄影和体格检查是等效的（但不是完全相同的），我希望两者的结合优于单独的任何一种方式。事实上，乳房X光检查和体格检查相结合的方法在所有指标上都优于单独的体格检查--除了死亡。乳房X光检查组的肿瘤平均比体格检查组的肿瘤小，并且更有可能是淋巴结阴性。米勒等人提供的数据显示，体格检查可将诊断日期提前1.5年，但增加乳房X线摄影可将诊断日期进一步提前2.1年。当然，如果身体检查是有益的，那么乳房X光检查肯定更有益。如果及早发现能提高治愈的前景，那么3.6年的准备时间肯定比1.5年的准备时间更可取。但事实并非如此。对该数据集的合理解释不是两种筛选方法等同，而是两种方法都无效。我认为，研究人员现在应该把注意力集中在理解为什么会出现这种情况上，并应该更加重视推进初级预防。
Miller et al. (1) report on the most recent results of a randomized trial of breast screening in Canada. At 16 years after randomization, there were 107 deaths observed among women randomly assigned to receive annual mammography plus physical examination and 105 deaths among a similar number of women randomly assigned to receive an annual physical examination alone. The authors interpret this to mean that that the two methods of screening were equivalent—i.e., that annual physical examination by a trained professional is a viable alternative to annual mammography and should be available to women 50 years old or older. This message has also been highlighted by several media reports covering the publication of the trial results. If this were a trial of mammography alone versus physical examination alone, this conclusion would be rational. However, if mammography and physical examination were equivalent (but not identical), I would expect the combination of the two to outperform either modality alone. In fact, the combination of mammography plus physical examination outperformed physical examination alone by every measure—except death. The tumors in the mammography arm were smaller, on average, than those detected in the physical examination arm and were more likely to be lymph node negative. Miller et al. present data showing that physical examination advanced the date of diagnosis by 1.5 years but that adding mammography advanced it further by 2.1 years. Surely, if physical examination were beneficial, then mammography must be more so. If early detection enhances the prospect of cure, a lead time of 3.6 years must be preferable to a lead time of 1.5 years. But this was not found to be the case. The rational interpretation of this dataset is not that the two screening methods were equivalent, but that neither was effective. I believe that researchers should now devote their attention to understanding why this is the case and should pay greater attention to advancing primary prevention.