Monday, October 22, 2018

PSA screening: USPSTF recommendations changed, but the evidence did not

- Kenny Lin, MD, MPH

Comparing the 2018 U.S. Preventive Services Task Force (USPSTF) recommendation statement on prostate cancer screening in the October 15th issue of AFP with its previous recommendation, the first question family physicians ought to ask is: what new evidence compelled the USPSTF to move from recommending against PSA screening in all men to determining that there was a small net benefit for screening in some men? Did another major randomized trial show a reduction in all-cause or prostate cancer-specific mortality in men invited to screening? Did other systematic reviewers re-analyze the evidence and find a mortality benefit where none previously existed? Have urologists or radiation oncologists developed new treatments for localized prostate cancer that no longer cause erectile dysfunction, urinary incontinence, or infections?

No, no, and no.

One of the Top 20 Research Studies of 2017 for Primary Care Physicians, the only U.S. trial of PSA-based screening for prostate cancer, reported that after a median followup of 15 years, there were still no differences in mortality between the two groups. In 2018, a large U.K. randomized trial of a single PSA screening also reported no effect on prostate cancer mortality after a median followup of 10 years. In both trials, more prostate cancers were diagnosed in the groups assigned to routine screening, but treating these cancers did not lead to improved health outcomes.

Last month, the authors of a 2010 Cochrane review of PSA screening (previously summarized in AFP's Cochrane for Clinicians) published an updated meta-analysis in the BMJ that incorporated the U.K. trial findings and extended followup of the U.S. and European screening trials and concluded that "at best, screening for prostate cancer leads to a small reduction in disease-specific mortality over 10 years but does not affect overall mortality." They also estimated that "for every 1000 men screened, approximately 1, 3, and 25 more men would be hospitalized for sepsis, require pads for urinary incontinence, and report erectile dysfunction, respectively." Another U.K. trial comparing active surveillance for localized prostate cancer with immediate surgery or radiation therapy found higher rates of clinical progression in the active surveillance group, but no differences in health-related quality of life or mortality.

Representing the views of American Academy of Family Physicians (AAFP), Drs. James Stevermer and Kenneth Fink explained in an editorial why "the AAFP believes that the net benefit [of PSA screening] does not justify routine screening or routinely offering shared decision making." The AAFP took the unusual step of declining to endorse the USPSTF recommendation statement and instead writing its own clinical preventive services recommendation that emphasizes the harms of routine screening. Men who bring up the topic of PSA screening should engage in shared decision-making with their physicians about the benefits and harms of screening and express a clear preference to be screened before undergoing the test.

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