Fewer men are being screened for prostate cancer, and fewer early-stage cases are being detected, according to two studies published Tuesday in The Journal of the American Medical Association.

11月17日发表在《美国医学协会杂志》(Journal of the American Medical Association)上的两项研究指出，接受前列腺癌筛查的人数有所减少，早期病例的检出量也在减少。

The number of cases has dropped not because the disease is becoming less common but because there is less effort to find it, the researchers said.

研究人员称，病例数减少并非是因为患病率正在下降，而是因为人们不像以往那么注意去检测这种疾病了。

The declines in both screening and incidence “could have significant public health implications,” the authors of one of the studies wrote, but they added that it was too soon to tell whether the changes would affect death rates from the disease.

其中一项研究的作者们写道，筛查和发病率的下降“可能具有重大的公共卫生意义”，但他们也补充说，要断言这一变化是否会影响该疾病的死亡率还为时过早。

About 220,800 new cases of prostate cancer are expected in 2015, along with 27,540 deaths, according to the American Cancer Society.

美国癌症协会(American Cancer Society)预计，2015年新发前列腺癌病例可达220800例，病死27540例。

Screening for prostate cancer, like mammography for breast cancer, has long been a subject of intense debate, with advocates insisting that it saves lives and detractors arguing that it leads to too much unnecessary treatment.

与使用乳腺摄影筛查乳腺癌一样，前列腺癌筛查长期以来也一直饱受争议，支持者们坚称它可以挽救生命，反对者则认为它会导致过多不必要的治疗。

The decrease in testing is almost certainly a result of a recommendation against screening made in 2012 by the United States Preventive Services Task Force. The task force, an independent panel of experts picked by the government, found that risks outweighed the benefits of routine blood tests for prostate-specific antigen, or PSA, a protein associated with prostate cancer.

几乎可以肯定，近期筛查测试的减少是2012年美国预防服务工作组(United States Preventive Services Task Force)提出建议反对筛查的结果。这一由政府挑选的独立专家小组发现，对前列腺特异性抗原（PSA，一种前列腺癌相关的蛋白质）进行常规验血检查的风险远远超过了其效益。

Because prostate cancer often grows slowly, the panel said, screening finds many tumors that might never have harmed the patient. But they are treated anyway. As a result, it concluded, testing saves few lives and leads too many men into unneeded surgery or radiation, which often leaves them impotent and incontinent.

该工作组指出，由于前列腺癌通常进展缓慢，筛查发现的许多肿瘤可能永远也不会对患者造成损害。但它们还是受到了治疗。因此，该检测救人不多，却害得太多人接受了不必要的手术或放疗，以致于阳痿或尿失禁。

An editorial accompanying the articles, by Dr. David F. Penson, the chairman of urologic surgery at Vanderbilt University Medical Center, acknowledged that too much screening could do harm but suggested that the pendulum had swung too far the other way.

范德堡大学医学中心(Vanderbilt University Medical Center)的泌尿外科主任戴维·F·彭森(David F. Penson)博士在随新研究刊发的评论文章中承认筛查过多可能有害，但也不至于像现在认为的那么夸张。

Rather than issuing a blanket recommendation against screening, Dr. Penson said, it would be better to “screen smarter” by testing most men less often and focusing more on those at high risk.

彭森博士并没有泛泛地建议反对筛查，相反，他认为更好的应对方法是“智慧地筛查”，即扩大筛查面，降低筛查频率，且更加关注高危人群。

One of the new studies, by researchers from the American Cancer Society, found that early-stage diagnoses of prostate cancer per 100,000 men age 50 and older dropped to 416.2 in 2012, from 540.8 cases in 2008, with the biggest decrease occurring from 2011 to 2012 — after a draft of the task force guidelines was released in October 2011. The authors estimated that the total number of diagnoses decreased to 180,043 in 2012 from 213,562 in 2011 — a difference of 33,519 cases.

其中一项新研究由美国癌症协会的研究人员完成，他们发现，前列腺癌的早期诊断率从2008年的每10万名年满50岁男性540.8例下降到了2012年的416.2例，最大的下降发生在2011年至2012年间，也就是2011年10月该工作组的指南发布之后。按照研究作者们的估算，总确诊病例数从2011年的213562例减少到了2012年的180043例，相差33519例。

That difference may indicate that many men were spared needless treatment — exactly what the task force had hoped to accomplish with its guidelines. But the authors also said, “Less screening or discontinuing screening may lead to missed opportunities for detecting biologically important lesions at an early stage and preventing deaths from prostate cancer.”

该差异可能代表有许多人避免了不必要的治疗，这也是该工作组希望其指南达到的目标。但作者们表示，“减少或中止筛查可能错失时机，以致未能在早期阶段发现具有重要生物学意义的病变，从而预防因前列腺癌死亡。”

The percentage of men 50 and older who reported PSA screening in the previous 12 months dropped to 30.8 percent in 2013, from 37.8 percent in 2010.

在年满50岁的男性中，报告在过去12个月内进行过PSA筛查者的比例从2010年的37.8%下降到了2013年的30.8%。

Although the study could not prove that the drop in screening caused the drop in diagnoses, the authors said it was the most plausible explanation.

尽管这项研究无法证明是筛查的减少导致了诊断数的下降，但作者们认为这是最合理的解释。

The findings were based on data from cancer registries and national surveys that asked men about prostate screening.

上述研究结果依据的是来自癌症登记局和有关前列腺筛查的全国性调查的数据。

A second study, by researchers from several medical centers, also found a significant decline in PSA testing after the 2012 task force recommendations.

在另一项研究中，多家医疗中心的研究人员也发现，自2012年工作组提出建议后，PSA检测显著减少了。

“With PSA testing, we often detect cancers that don’t need to be treated — clinically indolent, meaningless cancers,” Dr. Penson said in an interview. “It is true that more men die with prostate cancer than of it.”

“在PSA检测中，我们经常会发现临床上不活跃，也就是没有治疗意义的癌症，”彭森博士在接受采访时说。“但死于前列腺癌的男性要多于此，这也是事实。”

He said the recognition that many prostate cancers were indolent, or slow-growing, and not deadly had led to major changes in medical practice, making doctors less inclined to automatically operate if cancer is found.

他说，认识到许多前列腺癌并不活跃/生长缓慢/并不致命导致了医疗实践中的重大改变，医生们不像过去那样一发现癌症就不假思索地准备做手术。

The cancer society recommends that men discuss screening with their doctors to decide whether they should have it.

癌症协会建议男人们与他们的医生讨论后再决定是否应该接受筛查。

Some men, told the pros and cons, decide against having any screening. Others opt for the testing, and if cancer is found, want it removed even though it might not be deadly.

有些人在权衡利弊后决定不进行筛查。其他人则选择接受检测，而且，一旦发现癌症就立即切除——哪怕它可能并不致命。

But some who choose to be tested prefer another approach if cancer is found: “active surveillance,” which may involve repeated PSA tests and a biopsy every other year to find out if the cancer is growing and becoming more aggressive.

不过，也有一些选择接受检测的人倾向于在发现癌症后采取另一种方法：“主动监测”，包括多次PSA检测、每隔一年进行活检以确认癌症的生长情况，以及它是否正变得更有侵袭性。

Dr. James A. Eastham, the chief of the urology service at Memorial Sloan Kettering Cancer Center in New York, said two long-term studies had shown that this type of monitoring was a reasonable way to determine which patients needed treatment. Most patients considered low-risk turned out to have very low rates of cancer progression.

纽约纪念斯隆·凯特琳癌症中心(Memorial Sloan Kettering Cancer Center)的泌尿科主任詹姆斯·A·伊斯特汉(James A. Eastham)博士指出，两项长期研究表明，这种监测是识别哪些患者需要治疗的合适方法。大多数低风险患者的癌症进展率都非常低。

“Some do go on to treatment eventually, but the majority do not die of prostate cancer,” Dr. Eastham said. About 2 percent do die from the disease, he added. And he said that even with the best possible active surveillance, some patients will still be overtreated.

“一部分人最后还是去治疗了，但大多数人都没有因前列腺癌而死。”伊斯特汉博士说，大约2%的人死于这种疾病。他还说，即使在最好的主动监测之下，仍然会有一些患者被过度治疗。

Dr. Penson said that when active surveillance is explained, “of course men look and say, ‘That would be great if I can avoid having surgery or radiation.’ ”

彭森博士说，在向人们解释主动监测时，“他们当然会说：‘要是能避免手术和放疗，那感情敢情好。’ ”

“ ‘If you think this cancer is not a problem, Doc, I’ll take that every day and Sunday.’ It’s not hard to convince patients,” Dr. Penson added.

“他们会说：‘如果医生你觉得这处癌症没什么大不了的，我愿意天天监测。’所以要说服患者并不难。”彭森博士补充道。

Dr. Eastham and Dr. Penson said there had been two extremes in testing, neither satisfactory. First, doctors screened all men over 50 with PSA tests and operated on all cancers. But now they may be heading toward the other extreme of not screening anybody.

伊斯特汉博士和彭森博士表示，对待PSA检测出现过两个极端态度，它们都不尽如人意。早先是医生对所有50岁以上的男性都进行筛查，并对所有癌症都予以手术治疗。而今却又可能会走向对任何人都不筛查的另一个极端。

Both doctors said that screening should be based on a man’s preferences and individual risk, and that better ways to screen were needed, methods that would let doctors zero in on the cancers that needed to be treated and could be cured. Promising new imaging techniques and blood tests for biomarkers that would reveal cancer are in the works, they said.

两位博士都认为，筛查应基于个人偏好和个体风险，且需要更好的筛查方式，让医生可以将注意力集中在需要加以治疗且可以治愈的癌症之上。他们说，新的颇具前途的成像技术和生物标记物血液检测均在研究当中。

“But they’re not ready for prime time, so we’re stuck with the hand we’ve been dealt, the PSA test, which is an imperfect test,” Dr. Penson said. “But we can do a better job with it.”

“但它们还不够成熟，所以我们只能将就使用手头现有的这个差强人意的PSA检测，”彭森博士说。“不过，我们可以更好地利用它。”