Health

Routine PSA prostate cancer tests not recommended

Healthy men shouldn't get routine prostate cancer screenings, says updated advice from a U.S. government panel that found the PSA blood tests do more harm than good.

Healthy men shouldn't get routine prostate cancer screenings, says updated advice from a U.S. government panel that found the PSA blood tests do more harm than good.  

Despite strenuous protests from urologists, the U.S. Preventive Services Task Force is sticking by a contentious proposal it made last fall. A final guideline published Monday says there's little if any evidence that PSA testing saves lives — while too many men suffer impotence, incontinence, heart attacks, occasionally even death from treatment of tiny tumours that never would have killed them.

PSA screening often detects small tumours that will prove too slow-growing to be deadly. (CBC)

The guideline isn't a mandate. The task force stresses that men who want a PSA test still can get one, but only after the doctor explains the uncertainties. That's in part because the panel found PSA testing hasn't been studied adequately in black men and those with prostate cancer in the family, who are at highest risk of the disease.

The Obama administration said Monday that Medicare will continue to pay for PSA screenings, a simple blood test. Other insurers tend to follow Medicare's lead.

"This is important information for the public and men to have, and they should talk with their doctors about the risks and benefits of prostate cancer screening and make the decision that's best for them," said Mark Weber, a spokesman for the U.S. Department of Health and Human Services. 

In Canada, Ontario, Quebec and British Columbia do not cover the cost of most routine PSA prostate cancer screening tests.

Advice from the Public Health Agency of Canada:

  • All men over the age of 50 years should talk to their doctors about the potential benefits and risks of early detection of prostate cancer using the PSA test and the digital rectal examination test.
  • Men who are at higher risk because of family history or men of African ancestry should discuss the need for testing at an earlier age.
  • Insufficient evidence exists over whether the benefits of screening for prostate cancer outweigh the risks involved. There is no conclusive evidence that screening of asymptomatic men reduces mortality from the disease. At the same time, early diagnosis and treatment of cancers, which in many cases may not significantly progress during the patient's lifetime, can cause morbidity (e.g. impotence, urinary incontinence) leading to diminished quality of life.
Source: Public Health Agency of Canada

The U.S. task force advice goes a step further than major health groups including the American Cancer Society, which has long urged that men decide the issue for themselves after being told of PSA's pros and cons. But it's not likely to end an annual ritual for many men 50 and older. After all, the same task force has long urged men over 75 to skip PSA screening, and research suggests almost half of them still get tested. 

The controversy will end only with development of better tests — to finally tell which men's tumours really will threaten their lives, and who will die with prostate cancer rather than from it, said Dr. Virginia Moyer of the Baylor College of Medicine, who heads the task force.

"We have been told for decades to be terrified of cancer and that the only hope is early detection and treatment," she said. The reality: "You don't need to detect all cancers." 

"We don't want this to be the answer," Moyer added. "We want to screen for the ones that are going to be aggressive, manage those early — and leave everyone else alone."  

In an editorial published with the guideline in Annals of Internal Medicine, some urologists argue the panel underestimated the PSA test's value and overestimated its harms.  

"What PSA screening offers the men is a substantial opportunity to avoid dying a particularly unpleasant death from prostate cancer," said editorial co-author Dr. William Catalona of Northwestern University, who pioneered the testing.   

Competitors in British Columbia wear a giant pair of underwear to raise funds for prostate and other cancers that occur below the waist. Routine PSA screening for prostate cancer is in dispute. ((Darryl Dyck/Canadian Press))

He spoke Monday from a meeting of the American Urological Association, where doctors debated the guideline's impact. The urology association advises that men be informed of the potential risks and benefits before screening.  

But Dr. Otis Brawley, the American Cancer Society's chief medical officer, welcomed the task force's recommendation. He hoped it would help deter mass screenings, where men are given free PSAs at shopping malls and sports arenas without being told of the controversy, screenings that Brawley calls big business when health centres profit from the followup care.

"The question is, are we actually curing anybody who needs to be cured right now?" Brawley asked.

Dr. Robert Nam, head of genito-urinary cancer care at Sunnybrook Hospital in Toronto, has created a prostate risk calculator that factors everything from PSA tests to ethnic background to identify aggressive prostate cancer. He suggests biopsies and treatment only at that point.

"This is a process of selective screening. We are not going to go out there and biopsy everybody. At most we will monitor them. The benefit of screening is to find aggressive prostate cancer that will shorten your life."

Biopsies confirm prostate cancer

Too much PSA, or prostate-specific antigen, in the blood only sometimes signals prostate cancer is brewing. It also can mean a benign enlarged prostate or an infection. Only a biopsy can tell. Most men will get prostate cancer if they live long enough. Some 240,000 U.S. men a year are diagnosed with it, most with slow-growing tumours that carry a very low risk of morphing into the kind that can kill.

To evaluate whether routine screening saves lives, the task force analyzed previous research, focusing in particular on two huge studies in the U.S. and Europe. The panel's conclusion: 

  • Without screening, about five in every 1,000 men die of prostate cancer over 10 years. The European study found PSA testing might prevent one of those deaths, while the U.S. study found no difference.
  • Of every 1,000 men screened, two will have a heart attack or stroke from resulting cancer treatment, and 30 to 40 will experience treatment-caused impotence or incontinence.
  • Of every 3,000 men screened, one will die from complications of surgery.

Both the U.S. and European studies have flaws, and task force critics argue over which are most believable. And while U.S. death rates from prostate cancer have dropped over 20 years, the cancer society's Brawley says the drop began before PSA testing became widespread. Moreover, the risk of death is the same in Europe and the U.S. even though many more American men are screened, diagnosed and treated, he said.  

"We need to do a better job of using PSA wisely," said Dr. Scott Eggener, a University of Chicago prostate cancer specialist who was disappointed the task force went so far. "Most people would agree that a well-informed, young, healthy patient should have the opportunity to talk about it with their physician."

But he's studying a way beyond the screen-or-not controversy: Having men with small, low-risk tumours postpone treatment in favor of "active surveillance," keeping close watch on their tumours and treating only if they grow. More than 100,000 men a year are candidates, concluded a recent meeting at the National Institutes of Health.  

That approach could "maximize the benefits of screening," Eggener said.

With files from CBC News

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