PSA Tests for Prostate Cancer May Not Save Lives

Study Shows Routine PSA Tests Don't Cut Deaths; First Test at Age 60 May Be Best for Most

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Sept. 14, 2010 - Routine PSA screening tests for prostate cancer don't save lives.

That's the bottom line from a painstaking analysis of major clinical trials by University of Florida researcher Philipp Dahm, MD, and colleagues. They reviewed data on 387,286 men enrolled in six large clinical trials.

"We found no evidence to support the notion that prostate cancer screening improves overall survival or prostate cancer survival," Dahm tells WebMD. "It clearly increases the number of men diagnosed with prostate cancer. But based on high-quality evidence, there does not appear to be an impact on these two important outcomes."

Most U.S. men start getting PSA tests at about age 40. That's a good idea for men at high risk of prostate cancer: African-American men and men with a father, brother, or son who had prostate cancer before age 65.

Routine screening does, indeed, increase a man's chances of a prostate cancer diagnosis. For every 1,000 men screened, Dahm and colleagues find, 20 more cancers are diagnosed than in similar men who are not screened.

Nearly all of these cancers are early-stage cancers. But detecting these slow-growing cancers -- most of which will not be life threatening -- does not save lives.

Overdiagnosis of prostate cancer can lead to unnecessary treatments, including surgeries and radiation therapies that can leave men incontinent and/or impotent. Does this mean that routine PSA testing does more harm than good? Oddly enough, Dahm says, there's not enough study data to answer this question.

"Men diagnosed with prostate cancer typically get treated -- and we know there is a significant impact on quality of life: urinary function, erectile function, and so on. But none of these screening studies are comprehensive enough to look at what happens downstream to these patients," he says.

If saving lives is the point of routine PSA testing, the benefit is "not so great," says Gerald L. Andriole, MD, chief of urologic surgery at Washington University in St. Louis. Andriole's editorial accompanies the Dahm team's report in the Sept. 14 online issue of BMJ.

"When we do routine mass screening for prostate cancer there are winners and losers," Andriole tells WebMD. "Some men clearly benefit from early detection and early treatment. But other men are losers. They are diagnosed with a cancer, undergo unnecessary treatment and have side effects, and they go through all pain and anxiety associated with having cancer."

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1 PSA Test at Age 60?

The key question for men is not whether they have prostate cancer, suggests Hans Lilja, MD, PhD, of New York's Memorial Sloan Kettering Cancer Center. What they need to know is whether the cancer will cause symptoms or shorten their lives.

Lilja and colleagues wondered whether the PSA test could help men answer this question. To that end, they looked at a unique set of data collected from some 1,200 60-year-old Swedish men who donated blood plasma in a 1982 study of heart disease.

The researchers tested the blood for PSA levels. Then they matched the results to the men's medical records.

If men who had this single PSA test at age 60 had a PSA level of 1 ng/ml or less, they had a small chance of metastatic or fatal prostate cancer. By age 85, only 0.5% of these men had metastatic prostate cancer and only 0.2% of them had died of prostate cancer.

But men with age 60 PSA levels higher than 2 ng/ml were 17 times more likely to have metastatic prostate cancer by age 85 and 26 times more likely to die of prostate cancer than men with PSA levels below 2 ng/ml.

While 90% of the prostate cancer deaths by age 85 were in the men with an age-60 PSA level over 2 ng/ml, the finding was by no means a death sentence. Even among the 5% of men with the highest age-60 PSA levels -- at least 5.2 ng/ml -- only one in six died of prostate cancer.

Lilje tells WebMD that about half of men will have a PSA level of less than 1 ng/ml at age 60. If the study findings are validated in future studies, he says, it means that these men will never need another PSA test.

"Instead of screening everyone every year regardless of their PSA level the year before, you remove half -- those with a PSA below 1 -- because they would not benefit at all," Lilje says. "Instead, you would focus most of your effort on men with a PSA above 2, because they have the greatest chance of benefit."

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Andriole agrees with Lilje that the study findings must be confirmed in future studies with men from different ethnic groups. But he's excited about the implications.

"Maybe we can now target the men most likely to develop lethal prostate cancer and forget about men at very low risk," Andriole says. "Using the PSA test at late middle age, it segregates those who need further screening in a reasonable way. It is obviously not going to be perfect, but it is a good way to go."

The Lilje study also appears in the Sept. 14 online issue of BMJ.

Should Men Undergo PSA Testing?

So should men undergo PSA screening for prostate cancer? That remains a personal decision, Dahm says. But it is a decision that should not be made until a man has thoroughly discussed the possible benefits and possible harms with his doctor.

"People differ in their values and in their preferences and in what is important to them," Dahm says. "There clearly are men who, even if this is irrational, if they have prostate cancer they just want to know. But it is very important that we neither overrate nor underrate PSA screening. Our job as doctors is not to tell them what to do, but to provide them with accurate information."

And if a PSA test is high -- or even if a biopsy detects early prostate cancer -- Andriole advises men not to jump to conclusions, but to carefully consider their options.

"I would encourage patients with elevated PSA or with a prostate cancer diagnosis to really do a lot of homework, to ask a lot of questions, and to get familiar with the real terrain of early prostate cancer," he says. "You have time to make an informed decision. The resources to guide you are out there. Try not to get overly emotional and feel like you have to do something immediately."

WebMD Health News Reviewed by Laura J. Martin, MD on September 14, 2010

Sources

SOURCES:

Vickers, A.J. BMJ, published online Sept. 14, 2010.

Djulbegovic, M. BMJ, published online Sept. 14, 2010.

Andriole, G. L. BMJ, published online Sept. 14, 2010.

Hans Lilja, MD, PhD, Memorial Sloan Kettering Cancer Center, New York.

Gerald Andriole, chief of urologic surgery, Washington University School of Medicine, St Louis.

Philipp Dahm, MD, associate professor, University of Florida Department of Urology and Prostate Disease Center, College of Medicine, Gainesville, Fla.

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