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美专家小组建议女性不要每年做乳腺癌筛查

纽约时报 2016.1.21

2009年,一权威医学专家小组提出,女性并不像此前长期以来建议的那样需要接受那么多乳腺X线影像检查。这个观点引发举国哗然。该小组表示,乳腺癌风险为普通级别的女性无需从40岁起每年筛查,等到50岁以后开始每隔一年进行检查也一样安全。该小组还引用了大量的数据来支持自己的上述建议,并表示,目前尚无充足的证据确定对74岁以上女性进行常规乳腺摄影筛查是否还有价值。

原筛查方案的拥护者随即表达了自己的愤怒之情,称这些新建议将会延误诊断并导致更多的死亡。

1月11日,该小组更新了自己的指南,但并未让步,他们没有对适用于普通乳腺癌风险的妇女的基本建议作出更改。

预计这些建议不会立即影响到医疗保险的覆盖范围。去年12月,美国国会通过了一项法案,要求私营保险公司为年满40岁的妇女支付其每一到两年进行一次乳腺X线影像检查的费用,且不产生共付医疗费(copay,指超过了医保报销额度而需要患者自己支付的那部分医药费――译注)、共同保险(coinsurance)和自付额度。该法案的有效期到2017年为止。

但倡导组织表示,他们担心2017年之后会怎样。专注乳腺癌和卵巢癌早期检测和预防的全国性组织Bright Pink的办公室主任卡利・范斯坦(Carli Feinstei)说:“如果筛查能永远涵盖在医保范围内就太好了。”

苏珊・科曼乳腺癌防治基金会(Susan G. Komen For the Cure Foundation)也对医保报销问题表示忧虑,并发表声明称,如果不将乳腺癌筛查纳入保险范围之内,那么“本身风险就高且得不到足够医护服务”的妇女,尤其是黑人妇女将受害最深,因为她们比白人妇女更容易患侵袭性乳腺癌。

发布上述新指南的小组名为美国预防服务工作组(United States Preventive Services Task Force),这是一个由美国卫生和公众服务部(Department of Health and Human Service)指派的医生和其他专家所组成的独立委员会,其主要任务是评估那些旨在预防或及早发现疾病的筛查检测、咨询和药物。小组成员均为志愿者,其评估也只考虑到了科学证据,并没有涉及费用或保险覆盖面等问题。

该乳腺摄影筛查指南,以及四篇评论文章和七篇配套的支持性文章1月11日发表在《内科医学年鉴》(Annals of Internal Medicine)上。

该工作组强调,这些建议并不代表他们反对50岁以下或74岁以上的妇女进行筛查或每年筛查。更确切的说,他们认为女性应该自己选择――只是他们的指南提供了利益与风险的最佳综合平衡而已。

该工作组还审查了其2009年报告中未囊括的两个主题:一是对乳房组织呈“致密”状态的妇女进行MRI或超声等额外检查(因为此时使用乳腺摄影筛查也难以发现肿瘤);二是使用最新的三维乳腺摄影或数字化乳腺断层摄影来进行筛查。但他们的结论是:尚无足够的证据支持或反对其中任何一条。

乳腺癌是造成美国妇女因癌症死亡的第二大原因,仅次于肺癌。2015年,美国约有23.2万例乳腺癌新发病例,4万例死亡。55岁至64岁的妇女发病率最高。

康斯坦丝・莱曼(Constance Lehman)博士是哈佛医学院(Harvard Medical School)的放射学教授,也是美国麻省总医院(Massachusetts General Hospital)的乳腺影像科主任,但并非该工作组的成员。她表示,虽然工作组的建议最后并没有更改,但看到该小组比以往更加重视妇女选择何时开始筛查及筛查频率的自由,令她十分欣慰。

指南指出,在40岁到74岁的妇女中进行筛查都可以降低乳腺癌死亡率,40岁至49岁的妇女得益最少,而60岁至69岁的妇女受益最大。该工作组表示,他们有“中度把握”得出结论:50岁至74岁的妇女受益中等,而40岁至49岁的妇女受益较小。

工作组发现,对于每1万名在10年期间多次接受筛查的妇女,40岁至49岁年龄段中有4人避免了因乳腺癌死亡,在50岁至59岁年龄段中有8人,在60岁至69岁年龄段中有21人,在70岁至74岁年龄段中有13人。

工作组的前任主席,密苏里大学(University of Missouri)的医学教授迈克尔・勒菲弗(Michael LeFevre)博士说:“科学支持以乳腺摄影筛查作为与乳腺癌作斗争的重要工具。”他指出,自从20世纪80年代乳腺摄影筛查的广泛使用以来,乳腺癌的死亡人数有所减少(尽管其中也有一部分应该归功于更好的治疗方法)。“我们认为,收益随着年龄的增长而增加。只是筛查也有危害,尤其是对40多岁的女性,因此女性必须为自己拿主意。”

其中一个潜在的危害是假阳性,从乳腺摄影筛查结果来看疑似发现了病灶,结果做了更多的检测,甚至组织活检,最后却发现是一场虚惊。该指南依据的一项研究显示,在2003年至2011年间接受数字化乳腺摄影筛查的40.5191万名妇女中,假阳性十分常见,在较年轻的女性中尤其如此。在定期接受筛查的40岁至49岁妇女中,每1000人中就有121.2例假阳性。

2011年的另一项研究发现,在从40岁开始每年接受筛查的妇女中,有61%在50岁前至少遇到过一次假阳性结果。与每年筛查相比,每隔一年接受筛查时的假阳性率显著降低,约为42%。

另一个潜在风险是过度诊断,意即,在乳腺摄影筛查中发现的某些微小的癌症病灶可能永远不至于进展到会威胁患者的生命。但是,因为目前无法确知哪些癌症病灶将来会带来危险,因此就对它们一视同仁地进行了治疗。研究人员也认同过度诊断确有发生,但他们也不清楚其发生率如何。

休斯敦的得州大学MD安德森癌症中心(University of Texas M.D. Anderson Cancer Center)癌症防治中心(Cancer Prevention Center)的医务主任特蕾泽・贝弗斯(Therese Bevers)博士表示,她认为工作组过分强调了假阳性等不利因素的重要性。

纪念斯隆-凯特琳癌症中心(Memorial Sloan Kettering Cancer Center)的乳腺癌药物主管克利福德・A・休迪斯(Clifford A. Hudis)博士也表示担忧:“如果错过了本来可以治愈的癌症,将会贻害深远。在我看来,与此相比,接受不必要的活检造成的危害不值一提。”

权威医疗团体提出的建议各不相同,令妇女们及其医生在决策时不知所措。美国顶尖癌症中心的联盟――美国国家综合癌症网络(National Comprehensive Cancer Network)建议从40岁开始,每年进行乳腺摄影筛查。美国妇产科医师学会(American College of Obstetricians and Gynecologists)的建议是,在40岁到49岁之间每一年或两年筛查一次,其后每年一次。

去年10月,美国最有影响力的团体之一,美国癌症协会(American Cancer Society)撤回了自己原先的建议。虽然多年来该协会一直建议从40岁开始每年进行乳腺摄影筛查,但他们现在建议从45岁到54岁之间每年筛查,其后改为每隔一年筛查一次。

癌症协会、癌症网络和其他团体纷纷意识到了这种乱象,他们将于1月28日和29日在华盛顿举行私人会议,尝试制定一套统一的指南。

预防服务工作组的代表亦将参会,但工作组不能在一致的声明上署名。勒菲弗博士表示,他们只能通过发布新的指南来更改其建议。

Panel Reasserts Mammogram Advice that Triggered Breast Cancer Debate

New York Times

http://cn.nytimes.com/

2016.1.21

In 2009, an influential panel of medical experts ignited a nationwide uproar by suggesting that women needed fewer mammograms than had long been recommended. Instead of starting at age 40 and being screened every year, women with average risk of breast cancer could safely begin at 50 and be tested every other year, the group said, citing extensive data to support its advice. It also said that after 74, there was not enough evidence to determine whether routine mammography was worthwhile.

Outrage ensued, from advocates for screening who said the advice would lead to delayed diagnoses and deaths.

On Monday, the same panel issued an update of its guidelines ― and it is sticking to its guns. The basic advice, which applies to women with an average risk of breast cancer, was unchanged.

The recommendations are not immediately expected to affect insurance coverage. In December, Congress passed a bill requiring private insurers to pay for screening mammograms for women 40 and over every one to two years without copays, coinsurance or deductibles, through 2017.

But advocacy groups said they were worried about what will happen after 2017. “It would be great if screening could be covered forever,” said Carli Feinstein, chief of staff for Bright Pink, a national group focused on prevention and early detection of breast and ovarian cancer.

The Susan G. Komen for the Cure foundation also expressed concerns about insurance payment, and issued a statement saying that a lack of coverage would hit “high risk and underserved” women hardest, particularly black women, who are more prone than whites to aggressive types of breast cancer.

The panel issuing the guidelines is the United States Preventive Services Task Force, an independent board of doctors and other experts appointed by the Department of Health and Human Services to evaluate screening tests, counseling and medications intended to prevent disease or detect it early. Panel members are volunteers, and consider only the scientific evidence in their evaluations, not cost or insurance coverage.

The mammography guidelines, along with four editorials and seven supporting articles, were published on Monday in the Annals of Internal Medicine.

The task force emphasized that it was not advising against screening for women under 50 or over 74, or against screening every year as opposed to every other year. Rather, it says that women should choose for themselves ― but that its guidelines offer the best overall balance of benefits and risks.

The task force also examined data for two subjects not included in its 2009 report, and concluded that there was not enough evidence to recommend for or against either of them. One was additional testing, such as M.R.I. or ultrasound, for women with “dense” breast tissue, which makes it difficult to detect tumors with mammography. The other was screening with a newer test called 3-D mammography or digital breast tomosynthesis.

Breast cancer is the second-leading cause of cancer death in women in the United States, after lung cancer. In 2015, there were about 232,000 new cases of breast cancer, and 40,000 deaths. The highest incidence is in women aged 55 to 64.

Dr. Constance Lehman, a professor of radiology at Harvard Medical School and director of breast imaging at Massachusetts General Hospital, who is not on the task force, said she was pleased to see that although its advice had not changed, the group had placed more of an emphasis than before on the importance of women’s having the freedom to decide how often to be screened and when to start.

The guidelines state that from ages 40 to 74, screening will reduce the odds of dying from breast cancer, with women 40 to 49 benefiting the least and those 60 to 69 benefiting the most. The task force said it concluded “with moderate certainty” that the benefit was moderate in women 50 to 74 and small in women 40 to 49.

For every 10,000 women screened repeatedly over 10 years, four lives are saved in women 40 to 49; eight in women 50 to 59; 21 in women 60 to 69; and 13 in women 70 to 74, the task force found.

“The science supports mammography as an important tool in the fight against breast cancer,” said Dr. Michael LeFevre, a former chairman of the task force and a professor of medicine at the University of Missouri. He noted that breast cancer deaths have decreased since mammography came into widespread use in the 1980s, though some of the decline, he said, was also due to better treatments. “We believe the benefits increase with age. But there are harms, and particularly in their 40s, women have to make a decision for themselves.”

One potential harm is false positives, in which a suspicious mammogram finding leads to more tests, sometimes even biopsies, but turns out to be harmless. The guidelines relied in part on a study of records from 405,191 women who had digital mammograms from 2003 to 2011, which found that false positives were common, especially in younger women. Among those 40 to 49 who had regular screening, for every 1,000 women tested, 121.2 had a false positive.

Another study, in 2011, found that 61 percent of women who had yearly mammograms starting at age 40 had at least one false positive by the time they were 50. Being tested every other year instead of every year cut the rate of false positives significantly, to about 42 percent.

Another potential risk is overdiagnosis, meaning that some of the tiny cancers found in mammograms might never progress or threaten the patient’s life. But because there is now no way to be sure which cancers will turn dangerous, they are treated anyway. Researchers agree that overdiagnosis occurs, but they do not know how often.

Dr. Therese Bevers, medical director of the Cancer Prevention Center at the University of Texas MD Anderson Cancer Center in Houston, said she thought the task force overemphasized the importance of drawbacks like false positives.

Dr. Clifford A. Hudis, the chief of breast cancer medicine at Memorial Sloan Kettering Cancer Center, also expressed concern: “The harm of a missed curable cancer is something profound. The harm of an unnecessary biopsy seems somewhat less to me.”

Leading medical groups offer different advice about screening that leaves women and their doctors to puzzle it out for themselves. The National Comprehensive Cancer Network, an alliance of prominent cancer centers, recommends mammograms every year starting at age 40. The American College of Obstetricians and Gynecologists recommends them every year or two from ages 40 to 49, and every year after that.

In October, one of the most influential groups, the American Cancer Society, dialed back its advice. Although for many years the society recommended mammograms once a year starting at age 40, it now advises that screening start at 45, continue yearly through 54 and then shift to every other year.

Recognizing the confusion, the cancer society, the cancer network and other groups will attend a private meeting in Washington on Jan. 28 and 29 to try to produce a single set of guidelines.

Representatives from the preventive services task force will attend, but the task force cannot sign onto consensus statements. It can change its advice only by issuing new guidelines, Dr. LeFevre said.