A new strategy proposed by an international team of experts would limit the use of the prostate-specific antigen (PSA) test for screening tor prostate cancer to men who are younger than 70 years and who are at high risk or symptomatic.
This would reduce potential harms from overdiagnosis and overtreatment, the risk for which is high with the on-demand screening that is the current standard of care in most wealthy nations.
In a paper published online in The BMJ, the panel recommends instead a comprehensive nationwide program that would base PSA testing on individual patient risk and direct those with abnormal results to a managed system of imaging, targeted biopsy only if indicated, and subsequent active monitoring or treatment for those with more aggressive disease features.
Alternatively, government health programs could actively discourage widespread PSA testing and implement policies that would effectively limit PSA-based screening only to men with urologic symptoms warranting further exploration, said the authors, led by Andrew Vickers, PhD, a research epidemiologist at Memorial Sloan Kettering Cancer Center in New York.
“Although we believe that early detection of prostate cancer should involve shared decision making, the current approach of determining testing by shared decision making has resulted in the worst possible practical outcome of high levels of PSA testing and medical harm, with minimal benefit and inequity,” they wrote.
“To make better use of PSA testing, policy makers should choose between a comprehensive, risk adapted approach that is specifically designed to reduce overdiagnosis and overtreatment, or restricting PSA testing to people referred to urologists with symptoms. That choice will need to take into account wider patient and public perspective, as well as health economic concerns,” they continued.
Inappropriate testing
Since the Food and Drug Administration approved the first PSA screen in 1986 as a means for monitoring disease progression in patients being treated for prostate cancer, the test has remained controversial, embraced by some for its presumed ability to spot early prostate cancer but scorned by others for its equivocal results in patients with benign prostate pathology and for its potential to lead to overdiagnosis and overtreatment of low-grade disease in men who would otherwise be likely to die of other causes.
Currently, only Lithuania and Kazakhstan have government-supported population-based screening programs for prostate cancer. In contrast, the United States, United Kingdom, and other high-income countries have opted not to implement nationwide prostate cancer screening but allow so-called “informed choice testing,” in which men can receiving PSA screening after discussion with a primary care physician, urologist, or other specialist.
The U.S. Preventive Services Task Force recommends that for men aged 55-69 years, the decision to undergo PSA testing should be an individual one, based on an understanding of the risks and benefits. For men aged 70 or older, the task force flatly states, “Do not screen for prostate cancer.”
But as Dr. Vickers and colleagues noted, “high income countries that have made PSA testing available to men who request it after shared decision making with their physician now have a high prevalence of PSA testing with an inappropriate age distribution.”
For example, they pointed out that in the United Kingdom, men in their 80s are twice as likely as are men in their 50s to get a PSA test, even though men in the older age group are far less likely to have benefit and far more likely to experience harm from treatment. Similarly, in France, nearly one-third of men over 40 get an annual PSA test, with the highest incidence of PSA testing in men over age 70. There are also high rates of PSA testing in men over 70 in Italy, Germany, and Ireland.
“A key problem is that, in current routine care – and despite guidelines to the contrary – most men with an abnormal PSA result have prostate biopsy, even though only a minority will have aggressive prostate cancer,” Dr. Vickers and colleagues wrote. “Furthermore, most men with biopsy-detected cancers have either surgery or radiotherapy (with or without androgen deprivation therapy) even if they have low-risk tumors that are unlikely to cause cancer related morbidity or mortality.”
In addition, informed-choice PSA testing may lead to health inequities, the team noted, citing data from the United States, Canada, and Switzerland showing an inverse association between income and education and the likelihood of PSA testing. Also, in the United States and Canada, men from ethnic minority groups are less likely to have PSA testing.