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The Great Prostate Hoax:
How Big Medicine Hijacked the PSA Test and Caused a Public Health Disaster
By Richard Ablin and Ronald Piana
(Economist)
CHANCES are that either you have prostate cancer or you know someone who does. One in three men aged between 40 and 60 has traces of it, with the risk rising as men grow older. Nearly 240,000 new cases were detected in America last year, more than any other type of cancer. Faced with such facts, any man would be forgiven for wanting to find the invader and impale it—by any means necessary.
There is a raging debate, however, over whether that is wise. Some doctors insist that testing for a protein called prostate-specific antigen (PSA) helps detect prostate cancer early, making it far less lethal. Others contend that PSA screening has prompted a barrage of needless treatment. Among those who believe it does more harm than good is Richard Ablin, the author of “The Great Prostate Hoax”.
The prostate is a gland, about the size of a walnut, which helps make semen. It also makes the PSA protein. Mr Ablin, of the University of Arizona, claims to have been the first to identify PSA, though this is controversial. However, what matters is not who discovered it, but whether the protein provides any useful information. In some men with cancer, PSA levels may be elevated. But a high PSA does not necessarily mean that a man has cancer, nor does a low PSA mean he should be carefree.
Despite these shortcomings, the PSA test became common practice in the 1990s, particularly in America. In 1986 the Food and Drug Administration approved the test to monitor those already diagnosed with cancer. In 1994 it went further, authorising the test to help detect cancer in men aged 50 and older. A level of four nanogrammes per millilitre (ng/ml) became the standard threshold for a high PSA. William Catalona of Northwestern University, who argued for the test’s approval, admits that the cut-off of 4ng/ml was “completely arbitrary”. He created a scatter plot from data of men’s PSA levels and rates of cancer. “Just sort of eyeballing it, it looked like four would be a good number.”
What followed was a frenzied hunt for tumours. In America there were mass screenings in offices, in car parks and shopping malls. This was, in itself, harmless. PSA screening involves a simple blood test. The crucial question was what doctors and patients did once armed with the test’s imperfect information.
In the 1990s and early 2000s they did quite a lot. Doctors in America are rewarded for doing more procedures, so they often recommended biopsies to test for cancer. Almost 90% of cancers detected by PSA screening led to further treatment, such as radiation and prostatectomies. But it is unclear exactly how many of these treated cancers were indolent, unlikely to spread beyond the prostate’s lining.
Aggressive treatment can cause incontinence and impotence, which often lead people to seek yet further treatment, from penile implants to urinary cuffs. Attempts to avoid side effects have inspired new procedures, some of them of little value. Mr Ablin, and his co-author, Ronald Piana, are good at describing how the many ills of American health care—from doctors’ fears of malpractice suits to their fascination with new gizmos—conspired to encourage treatment. But this is a flawed book. Mr Ablin races down tangential lines of argument, making hyperbolic charges. Are the proponents of the PSA test really as bad as tobacco companies?
At the very least, though, he highlights the importance of the debate over whether PSA screening has helped or hurt patients. Deaths from prostate cancer dropped by 45% between 1993 and 2010, suggesting that the test may have helped. But the number of deaths began declining before PSA screening would have had much effect; screenings may also have identified cancers that were never going to become lethal, artificially raising survival figures.
Critics of PSA testing, once regarded as heretics, have gained credibility recently, as a result of two big new studies. An American trial reported that PSA screening brought a tiny increase in mortality, relative to a control group. A large European trial reported moderate benefit only in those aged 55-69; screening saved about one man for every 1,000 men tested. These studies helped convince a government panel in America to recommend in 2012 that no man be screened for his PSA levels.
The recommendation sparked a furore. The American Urological Association (AUA) declared itself to be “outraged”. Critics such as Dr Catalona said the trials were flawed. Now different doctors, faced with the same data, are drawing dramatically different conclusions. The result is a hodgepodge of practices both within America and outside it.
Last year doctors and academics at the Prostate Cancer World Congress recommended screening for those aged 50-69; a baseline test for men in their 40s was declared “useful”. The AUA urges “shared decision making” about screening for men aged 55-69 and “individualised” decisions for younger men with a higher risk of cancer. Andrew Vickers of Memorial Sloan Kettering, a top cancer centre in New York, says that screening has historically been done “very stupidly” in America, but insists that the PSA test is valuable. Sloan Kettering urges that men aged 45-70 be tested, then consider a biopsy if their level is 3ng/ml or more.
Otis Brawley, chief medical officer of the American Cancer Society, points to one obvious problem: “there is no natural cut point” that distinguishes safe from unsafe levels. Better tests are needed, he argues. Screening needs to identify the genetic traits that make one cancer indolent and another lethal. Companies have begun to bring such tests to market. They may eventually remedy the current problem. Once cancer is detected, men are determined to root it out, even when it might be safer to watch and wait. The PSA frenzy grew out of an all too common pair of human characteristics: the wish to defeat cancer at any cost and the imperfect understanding of how it works.
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