The debate over prostate cancer tests
Men of a certain age have heard the pitch many times: If they care about their health, they really should get their PSA checked. The simple blood test, men are told, can help uncover hidden cases of prostate cancer and potentially save their lives.
More than 20 million American men get their PSA measured each year. Doctors often include the test as a routine part of checkups for men older than 40, and many insurance companies flat-out require it. Cancer awareness campaigns frequently tout PSA tests as an important weapon against the disease, something like a male version of mammograms. The fact that prostate cancer kills more than 27,000 men a year may make the test seem like a no-brainer.
But when it comes to cancer screening, few things are as simple as they seem at first.
The PSA test is currently under attack on many fronts. While some experts credit the test with saving tens of thousands of lives each year, others say the benefits are over-hyped and might just be an illusion. And because treatments for prostate cancer can cause complications such as impotence and incontinence, there’s a growing fear that PSA testing ends up harming far more men than it helps.
A quick primer: Adult prostate glands make prostate specific antigen, or PSA, a protein that helps make semen. Healthy prostates tend to release only a trickle of the protein into the bloodstream, but cancer generally turns up the flow. Men with a PSA of more than 4 nanograms per milliliter of blood or with PSA readings that jump more than 0.35 ng/mL from one year to the next are usually offered a needle biopsy to check the prostate for cancer.
The American Cancer Society advises men to make their own decision about the test after talking to their doctors. But even if doctors are up to speed on the latest PSA studies — which is hardly a given — they probably don’t have time to discuss all the ins and outs of screening for prostate cancer, says Dr. Barnett Kramer, editor in chief of the Journal of the National Cancer Institute and an outspoken PSA skeptic.
“Men are left in the uncomfortable position of deciding whether to have a test where the benefits are uncertain but the harms, for many, are inescapable,” he says.
Some men choose to skip the test. Richard Ablin of Tucson is 70 and has never had his PSA checked. Not once. And it’s not because he’s uninformed. Quite the opposite: He’s the scientist who discovered PSA more than 40 years ago.
He doesn’t want congratulations for the test he helped make possible; he just wants it to go away. In an essay published last year in the New York Times, Ablin, a research professor of immunobiology and pathology at the University of Arizona, called PSA testing a “hugely expensive public health disaster.”
The test, he says, is inaccurate and misleading. Worse, it puts many man on a path toward invasive and life-changing treatments that they could easily have lived without. “We’re spending $3 billion a year on a test that cannot detect cancer,” he says. “I’ve been trying to put the kibosh on this for years.”
In fact, nearly 20 years after PSA tests first came into wide use, experts are still wrestling with a seemingly simple question: Does it save lives?
A 2009 study that followed more than 76,000 American men ages 55 through 74 for 10 years was supposed to provide the answer. Half the men were offered yearly PSA tests and the other half received “usual care,” which sometimes included the test. By the end of the study, 50 patients in the annual testing group had died of prostate cancer, compared with 44 patients in the usual care group. From a statistical point of view, screening didn’t seem to make any difference.
The study, while imperfect, should have been able to detect any lifesaving benefits had they existed, says lead researcher Dr. Gerald Andriole, a professor of surgery at Washington University School of Medicine in St. Louis. Researchers are continuing to follow the men and plan to publish an update sometime this year.
A similar randomized study, also published in 2009, followed more than 160,000 European men ages 55 through 69 for an average of nine years. This time, there was a survival difference: Men who received annual PSA tests were 20% less likely to die of prostate cancer than those who weren’t tested. A 2010 follow-up of this study that tracked more than 19,000 Swedish men for 14 years suggested that screening reduced cancer deaths by 44%.
Andriole sees a serious shortcoming in the European results: Unlike the American study, in which all patients with prostate cancer had access to roughly the same treatments, the Europeans who got the test also had better access to top-notch surgeons and aggressive hormone therapy than their untested peers. The treatment gap alone could largely explain why men who got the test were more likely to beat their disease, Andriole says.
When all the studies are taken together, he adds, the evidence suggests PSA testing might be most helpful for relatively young, healthy men who have at least 25 years of life ahead of them. Such men, he says, may want to get tested every couple of years. Doctors widely agree that the test won’t do much good for men in ther last 10 years of life, because prostate cancer grows so slowly that they’ll very likely die of something else first.
But even for younger men, the cost-benefit equation is murky.
Some of the murkiness stems from the fact that the test is far from perfect. Some men just naturally make a lot of PSA, and an infection or enlarged prostate can also cause a PSA spike. In fact, roughly two-thirds of men with a PSA over 4 don’t have prostate cancer, according to a position paper issued this year by the American Cancer Society. At the same time, biopsy studies have found cancer in nearly one-third of men whose PSA never reached the danger zone.
Even a rising PSA isn’t necessarily a sign of trouble. A study to be published this month in the Journal of the National Cancer Institute found that men whose PSA ticked upward over the course of a year were only slightly more likely than other men to have cancer. Researchers concluded that it doesn’t make sense to order biopsies for such cases unless there are other reasons to suspect cancer.
Another thing to muddy the waters: Though prostate cancer can certainly turn deadly, it’s a slow-growing disease that many man die with, not of. According to the American Cancer Society, as many as 40% of the prostate cancers discovered through PSA would have never caused any trouble if they had been left alone.
But once a man knows he has prostate cancer, it’s difficult to ignore. Most men want to get the cancer out of their body, but radical prostatectomy, or the surgical removal of the prostate, can lead to serious complications. Studies have found that about 20% of men who undergo surgery need to wear pads to control urine, and up to 80% have trouble getting or maintaining erections, according to the National Cancer Institute.
Dr. William Catalona, a pioneer of PSA testing who now practices urology at Northwestern University’s Feinberg School of Medicine in Chicago, believes the test catches enough cancers to justify the risks. Using the results of the Swedish study, Catalona estimates that yearly PSA screening of every American man 40 and older could save 22,000 lives each year. Some men should begin annual screening even earlier if there’s a history of prostate cancer in the family, he says.
And while he acknowledges that many prostate cancers are actually harmless, he says it’s impossible to predict which cancers will become deadly and which will not. “I just had a man [with advanced cancer] crying in my office with his wife,” Catalona says. “It was completely preventable.”
Dan Zenka, vice president of communications for the Prostate Cancer Foundation in Santa Monica, says a PSA test last year saved his life. After the test came back as a worrisomely high 5.8, a biopsy revealed a relatively advanced case of cancer at the age of 51. The radical prostatectomy went smoothly without any complications. “I’d like any opponent to look me in the eye and tell me that I shouldn’t have had a PSA test,” he says.
Many men feel they owe their lives to the PSA, and it’s hard to argue with people like Zenka. But the numbers suggest that true “PSA survivors” are a rare breed. The researchers behind the large European study estimated that 1,410 men would have to be screened repeatedly and 48 men would have to be treated for prostate cancer to save one life.
So is the PSA test worth it? Men who fear cancer above all else may well want to get screened despite all of the uncertainties, Andriole says. But, he adds, if a man decides to skip the test, he’s not being reckless. It’s his prerogative. And his prostate.