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2017 USPSTF on PSA: A Bad Idea

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Richard J. Ablin, Ph.D., D.Sc. (hon), Dr. h.c. Professor, Department of Pathology, University of Arizona College of Medicine, The Arizona Cancer Center and BIO5 Institute, Tucson, AZ 85724. Ronald Piana, Freelance Science Writer, Huntington, NY 11743

Q: The new draft USPSTF recommendations for rapid comment on use of PSA for screening represent a big change from 2012. They now read: “The decision about whether to be screened for prostate cancer should be an individual one. The USPSTF recommends that clinicians inform men ages 55 to 69 years about the potential benefits and harms of prostate-specific antigen (PSA)–based screening for prostate cancer” and much more. Shared patient-physician decision making. What do you think? (For last week’s answer to the same question see here)

A: In a troubling reversal of its previous Recommendation against the use of prostate-specific antigen (PSA) screening, the US Preventive Services Task Force has issued a Draft Recommendation that doctors should have a meaningful conversation with male patients between the ages of 55 and 69 about the risks and benefits of undergoing PSA screening. This is a bad public health decision that will only increase the use of an intrinsically flawed test that—as formally noted by the Task Force—does far more harm than good.
Screening to identify preclinical and asymptomatic disease in a population at risk is one of the cornerstones of preventive medicine. However, the success of a screening program depends on the specificity of the test for the disease in question and early identification of these patients must convey a clinical (treatment) advantage. Screening for prostate cancer generally begins with a PSA test, which is specific for a protein in the prostate gland but not for cancer. Moreover, there is no level of PSA diagnostic for prostate cancer; PSA cannot distinguish a harmless, slow-growing cancer from an aggressive one. It’s important to note that prostate cancer is an age-related disease and upward of 80% of men screened will have asymptomatic cancer irrespective of their PSA level, which leads to overdiagnosis and unnecessary treatments that to date have left countless millions of men incontinent and impotent, not to mention the healthcare costs and emotional turmoil that a positive PSA test introduces.
The Task Force’s new Draft Recommendation centers on a doctor-patient informed-decision conversation about PSA screening, across all social and demographic lines. Given the complexity of this issue, it is not feasible for a busy community doctor to elucidate the full spectrum of detailed clinical issues involved in PSA screening.1 Inequities and variability will abound, as is borne out by data. For example, a new study2 that looked at 200,000-plus men found that 37 percent were told only of the advantages of PSA compared with 30 percent who were advised of advantages and disadvantages. More striking, 33 percent were not informed of either. These men were more likely to be Hispanic, not high school graduates, and of low income. Basing a potentially life-changing medical decision on incomplete information will have profound consequences for men across the country.
The Task Force indirectly suggests that doctors and patients should revisit the decision to screen (or not screen) in a Table presented in the Draft Recommendation of estimated effects of PSA-based screening for prostate cancer on men observed in the ERSPC trial. A relevant caveat here3is that the ERSPC trialists have yet to de-identify patient data and make it available for independent review. Without examining individual patient data, it is impossible to confirm any benefit of PSA screening or the validity of the data.
Before the Draft Recommendation goes into effect, doctors across the country need specific guidance from the Task Force on how to conduct informed-decision-making conversations with their patients about PSA testing. It is recommended that the Task Force create a discussion summary similar to the Table included with the Draft Recommendation. Thereby all patients will receive consistent information so that they can make their own assessment of the potential benefits or harms resulting from the PSA test.

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