Men should not get routinely screened for prostate cancer using the PSA test, a government panel recommends. The panel finds there is little evidence that testing for PSA, or prostate-specific antigen, saves men’s lives, and that it causes too much unnecessary harm from the treatment of tumors that would never have killed them.
The advice, published [PDF] by the U.S. Preventive Services Task Force in the Annals of Internal Medicine, extends the recommendation against routine prostate-cancer screening to men of all ages. The group had previously advised men ages 75 and older to avoid PSA testing.
The USPSTF, which in 2009 recommended that women delay routine mammograms until age 50, based its prostate-cancer-screening guidelines on a review of previous research, including two large studies in the U.S. and Europe. The studies compared cancer rates and survival between men who were routinely screened and those who were not, and found little to no mortality benefit from PSA screening over 10 years of follow-up.
The panel concluded that the benefit of screening was not outweighed by the potential risks, which include pain, fever, bleeding, infection and problems urinating, resulting from biopsies as well as incontinence and impotence associated with the treatment of tumors that would not have otherwise caused harm. Each year, about 1,000 to 1,300 men die from complications associated with treatments prompted by PSA screening.
The task force’s recommendation goes against two decades of widespread use of the PSA test — a $35 blood test that detects levels of prostate-specific antigen, a protein that may indicate the presence of prostate tumors.
“The recommendation is not just counter to what the lay public has been taught about cancer prevention but what physicians have been taught as well,” says Dr. Michael LeFevre, co–vice chair of the USPSTF and a professor of family and community medicine at University of Missouri. “We’ve been told for decades to be afraid of cancer and that the only hope is early detection and treatment. So it’s hard for physicians and patients alike to accept that not all cancers need to be detected or need to be treated and that there are harms associated with screening, not just benefits.”
The panel’s conclusion may be confusing to patients and physicians in part because they have likely assumed that previous clinical recommendations for prostate-cancer screening were based on extensive and solid scientific studies. In reality, PSA screening had not been fully evaluated for its survival benefits. Most previous studies had focused on five-year survival rates: although men who got PSA testing were more likely to survive five years after being diagnosed, compared with those who did not get screened, PSA testing does not necessarily extend their lives overall.
“They were finding the cancer earlier, so the time from diagnosis to death was longer, but the patient wasn’t actually living longer,” says Dr. Otis Brawley, chief medical officer of the American Cancer Society. “So these men were living a longer proportion of their lives knowing they have cancer, but they weren’t dying at a later date.”
That distinction is important, he says, since it means early detection is not necessarily better. Rather, PSA testing could result in many men being overdiagnosed with prostate cancer. That’s especially problematic for prostate tumors, since they grow very slowly in many cases and don’t cause health problems for older men. Most doctors say many men die with prostate cancer, not from it. One large study, the Prostate Cancer Prevention Trial, showed that while 28% of men in their 60s were diagnosed with prostate cancer after showing high level of PSA, only 3% of those men ultimately died of the disease.
So when the USPSTF compared the low risk of death from prostate cancer against the likelihood of complications due to unnecessary treatments resulting from screening, it concluded that PSA testing did more harm than good. What’s missing, says Brawley, is a better way to predict whether prostate cancer will be deadly or not; doctors need a more sophisticated way to distinguish the tumors that are more likely to cause serious disease, and therefore need to be treated, from those that aren’t likely to cause health problems that warrant intervention. The current PSA test isn’t molecularly sophisticated enough to do that.
Which is why, for nearly a decade now, major cancer and health organizations have not advocated for routine prostate-cancer screening in men the same way they recommend mammography for breast-cancer screening in older women. Instead, experts have advised men to begin discussing their risk-factor profile with their doctors in their 50s, when prostate-cancer rates start to rise, to determine whether a PSA test makes sense for them.
Some experts are concerned, however, that the USPSTF recommendation may have the unintended effect of closing off all discussion of prostate cancer and prostate-cancer screening between doctors and patients during routine medical visits. Most primary-care physicians rely on the USPSTF recommendations as a guideline for what to discuss with their patients, and if the task force advises against PSA testing, then it may fall to the patient to bring up the issue of his risk factors and ask whether he should be getting the test.
“If we stop offering the PSA and put a gag across our mouths, saying we shan’t talk about it at all, there will be men whose lives could be saved who won’t be saved,” says Dr. Ian Thompson, chairman of the prostate-cancer panel of the American Urological Association. “While the task force made its recommendation on a population level, it’s implemented at a very personal level. And that’s complicated.”
Rather than coming to a blanket conclusion that no men should be screened with PSA, Thompson says emphasizing the value of screening on an individual basis might be more helpful, to ensure that men are not unnecessarily allowed to progress to advanced stages of cancer when it becomes less treatable. Since PSA testing has been implemented, he says, rates of prostate-cancer deaths have dropped by almost 50%; advances in treating early tumors, with hormone therapy and low-dose radiation, may also be lost if more cancers are diagnosed at later stages, when those therapies are no longer effective. “To completely say, Don’t do [PSA testing] at all — I have a little difficulty with that,” he says.
However, the USPSTF stresses that men who want a PSA test can still get one and that doctors may offer it as long as they explain the risks and benefits to patients.
But LeFevre says it may be time to accept that our understanding of cancer is changing, and with that, our ways of detecting and treating it will need adjustment. “We formulated this dogma that all cancer needs to be detected early and that treatment was our only hope decades ago when our ability to get in and find asymptomatic disease was limited and almost negligible. At that time, the assumption was that any cancer we found was the bad kind. But the more technology advances to detect asymptomatic disease, the more we learn that not all of it needs to be detected. It’s a different way of thinking about asymptomatic disease, that not all of it goes on to make people sick.”
But as with any change, it will be hard to accept that screening isn’t always good.
HEALTH SPECIAL: Cancer — the Screening Dilemma