新研究对乳腺癌X光筛查提出进一步质疑

One of the largest and most meticulous studies of mammography ever done, involving 90,000 women and lasting a quarter century, has added powerful new doubts about the value of the screening test for women of any age.历史上规模仅次于、最严苛精细的乳房X光检查研究之一，对所有年龄段的女性展开这种筛查的价值明确提出了强有力的新批评。这项研究持续了四分之一个世纪之幸，牵涉到9万名女性。It found that the death rates from breast cancer and from all causes were the same in women who got mammograms and those who did not. And the screening had harms — one out of five cancers found with mammography and treated was not a threat to the womans health and did not need treatment like chemotherapy, surgery or radiation.该研究找到，在做到过乳房X线检查和没做到过它的女性中，乳腺癌造成的死亡率和所有原因造成的死亡率并无二致。

而且这种筛查本身具备危害——通过乳房X光检查找到并展开了化疗的癌症肿块中，有五分之一对女性的身体健康并不构成威胁，也不必须展开化疗、手术或超声等化疗。The study, published Tuesday in The British Medical Journal, is one of the few rigorous evaluations of mammograms conducted in the modern era of more effective breast cancer treatments. It randomly assigned Canadian women to have regular mammograms and breast exams by trained nurses or to have breast exams alone.这项研究本周二公开发表在《英国医学杂志》(BMJ)上，在如今这个乳腺癌化疗手段更为有效地的时代，对乳房X线检查展开的严苛评估寥寥无几，它就是其中一个。在这项研究中，加拿大女性被随机分配给训练有素的护士，展开定期乳房X光检查和乳房检查，或者只展开乳房检查。

Researchers sought to determine whether there was any advantage to finding breast cancers when they were too small to feel. The answer was no, the researchers report.研究人员期望确认，在乳腺癌肿块太小，患者感觉将近它的时候，找到乳腺癌否有任何优势。答案是驳斥的，研究报告称之为。The study seems likely to lead to an even deeper polarization between those who believe that regular mammography saves lives, including many breast cancer advocates and patients, and a growing number of researchers who say the evidence is lacking or, at the very least, murky.这项研究很可能会造成加深的两极分化：一方是坚信定期做到乳房X光检查可以挽回患者生命的人，还包括很多乳腺癌关怀活动倡导者和患者，另一方是更加多的研究人员，他们指出这种众说纷纭缺少证据，或者最少是证据不明朗。It will make women uncomfortable, and they should be uncomfortable, said Dr. Russell P. Harris, a screening expert and professor of medicine at the University of North Carolina. The decision to have a mammogram should not be a slam dunk.“这不会让女性深感不难受，她们也理所当然深感不难受，”筛查专家、北卡罗莱纳大学(University of North Carolina)医学教授拉塞尔·P·哈里斯(Russell P. Harris)说道。

“要求做到乳房X光检查本来也不应当是一桩乐事。”The findings will not lead to any immediate change in guidelines for mammography, and many advocates and experts will almost certainly dispute the idea that mammograms are on balance useless, or even harmful.这些研究结果会马上造成乳房X光检查准则的变更，很多倡导者和专家完全认同不会对“乳房X线检查总体多余，甚至危害”的观点展开批评。Dr. Richard C. Wender, chief of cancer control for the American Cancer Society, said the society has convened an expert panel that is reviewing all studies on mammography, including the Canadian one, and would issue revised guidelines later this year. He added that combined data from clinical trials of mammography showed it reduces the death rate from breast cancer by at least 15 percent for women in their 40s and by at least 20 percent for older women.理查德·C·文德(Richard C. Wender)博士是美国癌症协会(American Cancer Society)癌症掌控主任，他说道该协会早已开会了一个专家小组，正在审查和乳房X光检查有关的所有研究，加拿大的这项研究也还包括在内，今年晚些时候，他们将公布修改后的准则。

他还说道，乳房X光检查的临床试验的综合数据表明，在40多岁的女性中，乳房X光检查最少减少了15%的乳腺癌死亡率，在年龄更大的女性中减少了最少20%。That means that one woman in 1,000 who starts screening in her 40s, two who start in their 50s and three who start in their 60s will avoid a breast cancer death, Dr. Harris said.这意味著，在40多岁开始筛查的1000名女性中，有一名将防止杀于乳腺癌，50岁开始的有两名，60岁开始的有三名，哈里斯博士说道。Dr. Wender added that while improved treatments clearly helped lower the breast cancer death rate, so did mammography, by catching cancers early.文德博士认为，提高后的化疗方法似乎有助减少乳腺癌死亡率，做到乳房X光检查也是一样，因为可以提前找到癌症。

But an editorial accompanying the new study said that earlier studies that found mammograms helped women were done before the routine use of drugs like tamoxifen that sharply reduced the breast cancer death rate. In addition, many studies did not use the gold-standard methods of the clinical trial, randomly assigning women to be screened or not.但跟这项新的研究同时公开发表的一篇社论说道，那些找到乳房X光检查不利于女性的早期研究，是在如今常规用于的药物大幅度减少乳腺癌死亡率之前展开的，这些药物还包括他莫昔芬(Tamoxifen)；此外，很多研究没使用标准最低的临床试验方法，随机分配女性否拒绝接受筛查。Dr. Mette Kalager, an epidemiologist and screening researcher at the University of Oslo and the Harvard School of Public Health who wrote the editorial, said there was a reason its results were unlike those of earlier studies. With better treatments, like tamoxifen, it was less important to find cancers early. Also, she said, women in the Canadian studies were aware of breast cancer and its dangers, unlike women in earlier studies who were more likely to ignore lumps.这篇社论的作者梅特·卡拉格(Mette Kalager)博士是奥斯陆大学(University of Oslo)和哈佛大学公共卫生学院(Harvard School of Public Health)的流行病学家和筛查研究员，她回应，这项研究的结果不同于早期的那些研究是有原因的。

有了更佳的化疗手段，比如他莫昔芬，提前找到癌症肿块就不那么最重要了。此外她还回应，加拿大那项研究中的女性理解乳腺癌及其危险性，而早期研究中的女性更加有可能会忽略肿块。

It might be possible that mammography screening would work if you dont have any awareness of the disease, she said.“如果你几乎没乳腺癌的意识，乳房X光检查就有可能效果不俗，”她说道。The Canadian study reached the same conclusion about the lack of a benefit from mammograms after 11 to 16 years of follow-up, but some experts predicted that as time went on the advantages would emerge.在展开了11到16年的复查随访后，加拿大这项研究得出结论了乳房X线检查没裨益的某种程度结论。但一些专家预计，随着时间的流逝，乳房X线检查的优势将不会显出。That did not happen, but with more time the researchers could, for the first time, calculate the extent of overdiagnosis, finding cancers that would never have killed the women but that led to treatments that included surgery, chemotherapy and radiation.这种情况还没经常出现，但因为多花上了一些时间，研究人员首次计算出来出有了过度临床的程度，即针对绝不会令其女性遇难的癌症肿块，实行手术、化疗和超声等化疗手段。

Many cancers, researchers now recognize, grow slowly, or not at all, and do not require treatment. Some cancers even shrink or disappear on their own. But once cancer is detected, it is impossible to know if it is dangerous, so doctors treat them all.研究人员现在认识到，很多癌症肿块生长缓慢，或显然不生长，也不必须化疗。有些癌症肿块甚至不会衰退或自行消失。但是，一旦癌症肿块被检测到，你就不告诉它否不会带给危险性，所以医生不会统统展开化疗。In the United States, about 37,000,000 mammograms are performed annually at a cost of about $100 per mammogram. Nearly three-quarters of women age 40 and over say they had a mammogram in the past year. More than 90 percent of women ages 50 to 69 in several European countries have had at least one mammogram.美国每年约要做到3700万例乳房X线检查，每次检查的费用大约为100美元（约合人民币600元）。

40岁及以上的女性有四分之三回应曾在过去一年里展开过乳房X光检查。在几个欧洲国家，年龄在50至69岁的女性中有多达90%最少展开过一次乳房X光检查。Dr. Kalager, whose editorial accompanying the study was titled Too Much Mammography, compared mammography to prostate-specific antigen screening for prostate cancer, using data from pooled analyses of clinical trials. It turned out that the two screening tests were almost identical in their overdiagnosis rate and had almost the same slight reduction in breast or prostate deaths.卡拉格博士关于这项研究的社论标题是《乳房X光检查洪水泛滥》(Too Much Mammography)，文中用于来自临床试验的汇总分析数据，把乳房X光检查跟前列腺癌的前列腺特异性抗原（PSA）筛查相提并论。数据表明，这两种筛查的过度诊断率完全完全相同，在减少乳腺癌或前列腺癌死亡率的效果方面也完全某种程度严重。

I was very surprised, Dr. Kalager said. She had assumed that the evidence for mammography must be stronger since most countries support mammography screening and most discourage PSA screening.“我深感十分吃惊，”卡拉格博士说道。她原以为反对乳房X光检查的证据认同不会更为有力，因为大多数国家都反对乳房X光筛查，赞成PSA筛查。

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