PSA Screening: Has the Death Knell Been Sounded?

No, Say Experts, But Change Is Needed

Zosia Chustecka

October 28, 2011

October 28, 2011 — The ongoing controversy about using prostate-specific antigen (PSA) to screen healthy men for prostate cancer — which came to a head recently when the United States Preventive Services Task Force (USPSTF) recommended against regular screening — continues in a series of papers published online October 26 in the New England Journal of Medicine.

Screening for prostate cancer using PSA is "the controversy that refuses to die," writes one set of authors, but they wonder whether this latest recommendation against regular screening will "finally sound the death knell for the PSA controversy."

Mary McNaughton-Collins, MD, MPH, and Michael Barry, MD, from Harvard Medical School and Massachusetts General Hospital, Boston, write in their commentary that they agree with the USPSTF conclusions about potential harms from screening, but "we have a different perspective on the key question of benefit."

They argue that there is evidence for "a possible small but finite benefit" from PSA screening; in their opinion, this evidence of benefit is sufficient to tip the USPSTF recommendation from a D grade (which discourages the use of this service) to a C grade (which discourages routine screening but acknowledges that there might be value in providing the service to an individual patient).

However, a C grade would come "with considerable responsibility for primary care physicians," they write. "We cannot simply pay lip service to shared decision making," and there would have to be practice changes, including detailed discussions with patients about the pros and cons of testing, in order for a grade C recommendation to be reasonable, they add.

"We owe it to our patients to provide them with the kind of guidance about this screening test that they need and deserve," Drs. McNaughton-Collins and Barry conclude. "That's the way to help put the controversy to rest...one man at a time."

Individualizing the Decision

Also highlighting the need to individualize the decision of whether to screen or not is a commentary by Fritz Schröder, MD, from the Erasmus University Medical Center in Rotterdam, the Netherlands.

Dr. Schröder was the principal investigator of the European Randomized Study of Screening for Prostate Cancer (ERSPC), which found a mortality benefit from PSA screening — in contrast to the lack of effect found in the large American study published at the same time.

He takes issue with the way the USPSTF analyzed some of the data from that positive European study, and emphasizes that when the analysis is adjusted to follow men who actually underwent screening, it shows a large drop in prostate-cancer mortality — of 27% after 9 years of follow-up and of 56% after 14 years. Dr. Schröder also emphasizes a secondary end point of prostate cancer morbidity, and notes that a preliminary analysis suggests that screening reduces the relative risk for metastatic disease by 41%.

"PSA screening should not be dismissed as uniformly nonbeneficial," he writes. "Instead, decisions about screening should be made on an individual basis by an informed patient and his clinician, after weighing that particular patient's risk factors."

To aid in this decision making, Dr. Schröder suggests using the prostate risk calculator, which is based on data that came out of the ERSPC trial.

Other aids for decision making are recommended in a report by Richard Hoffman, MD, MPH, from the University of New Mexico School of Medicine in Albuquerque. He suggests that clinicians direct their patients to tools produced by the US Centers for Disease Control and Prevention — such as their screening decision guide and their screening decision guide for African Americans, who are at higher risk of prostate cancer.

Dr. Hoffman emphasizes the potential harms from screening, including overdiagnosis and overtreatment, which can lead to complications such as urinary, sexual, and bowel dysfunction. These need to be balanced against "the small absolute disease-specific survival benefit," he says.

Not the End of the Controversy

The USPSTF recommendations are unlikely to end the PSA controversy, but "a document finally exists that should provide guidance to clinicians and policymakers," according to a commentary by Allan Brett, MD, from the University of South Carolina School of Medicine in Columbia, and Richard Ablin, PhD, from the University of Arizona College of Medicine in Tucson. Forty years ago, Dr Ablin discovered a PSA, and he has spoken out against its use for routine screening. He recently told Medscape Medical News that he was pleased with the USPSTF recommendation against routine use of the PSA test, and felt vindicated, because it was never a use that he had envisioned or advocated.

Reiterating the point that PSA is not specific for prostate cancer, Drs. Brett and Ablin highlight "the variable and often idiosyncratic management of PSA levels in primary care and urology practices."

Men are tested and retested — sometimes several times a year — hoping to hear that their PSA levels "went down" or "at least didn't go up," they point out. Some men undergo repeated biopsies after small spikes in PSA levels, and others are treated with antibiotics for presumed prostatitis, even though a recent trial showed no effect of antibiotics on PSA level.

"These approaches to managing serial PSA levels reflect either a fundamental misunderstanding — or an unwillingness to acknowledge — PSA's limitations as a marker for early prostate disease," they write.

One other point about screening — which only they make — concerns cost. "Policymakers cannot ignore economic aspects of screening," they write.

Using data from the ERSPC trial, researchers have estimated that $5.2 million would have to be spent on screening (and the interventions that follow it) to prevent 1 death from prostate cancer. That estimate does not appear to include the costs of excessive PSA testing and the repeated office-based encounters devoted to discussing fluctuating PSA levels, they note.

"The extraordinary time, effort, and cost associated with the PSA screening enterprise must be evaluated against other claims on healthcare spending and physician's time and energy," Drs. Brett and Ablin note.

"We believe that the current PSA screening paradigm does not compare favorably with competing healthcare priorities," they conclude.

N Engl J Med. Published online October 26, 2011. McNaughton-Collins and Barry, Schröder, Hoffman, Brett and Ablin

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