Three recent papers in NEJM span a range of physicians’ reactions to the US Preventative Services Task Force draft recommendations for prostate cancer screening via the PSA test. The USPSTF suggests a grade of D for the PSA test, which means that it “recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.” Thus, a D grade is meant to “Discourage the use of this service.”
Below are excerpts from the three NEJM papers followed by a brief commentary. They’re all ungated so you can click through to read the details.
1. Prostate-Cancer Screening — What the U.S. Preventive Services Task Force Left Out, by Allan Brett and Richard Ablin. The authors are supportive of the draft recommendations.
- Before results of recent clinical trials “it was impossible to address [the] probabilities and uncertainties coherently during routine office visits. Thus, patients were not really making informed decisions, and office based discussion of the pros and cons of PSA testing was essentially a charade. Instead, most patients’ decisions reflected their general concerns about cancer or their general inclination to accept (or resist) medical interventions.”
- Many common “approaches to managing serial PSA levels reflect either a fundamental misunderstanding of — or an unwillingness to acknowledge — PSA’s limitations as a marker for early prostate cancer.”
- Many so called “PSA-detected” cancers “are not really detected by PSA screening; they are incidental findings against a background of randomly fluctuating PSA levels and an age-related increase in prostate cancer incidence.”
- “[G]uidelines are vague precisely because the limitations of PSA screening preclude the kind of rational, standardized, evidence-based algorithm that should inform any routine preventive intervention.”
- “[R]esearchers have estimated that $5.2 million would have to be spent on screening (and the interventions that follow it) to prevent one death from prostate cancer.”
- “For two decades, primary care physicians have been expected to present a flawed screening test to patients, cloaking the flaws in an elaborate ritual of informed decision making. In turn, men have been expected to make sense of a confusing mix of hypothetical outcomes. Although the USPSTF recommendation is unlikely to end the PSA controversy, a document finally exists that should provide guidance to clinicians and policymakers.”
2. Stratifying Risk — The U.S. Preventive Services Task Force and Prostate-Cancer Screening, by Fritz Schröder. The author is generally dissatisfied with the draft recommendations.
- “[T]he USPSTF report has a number of key weaknesses.”
- “[I]t relied heavily on a meta-analysis that combined higher- and lower quality evidence.”
- “[The] PSA screening should not be dismissed as uniformly nonbeneficial. Rather, decisions about screening should be made on an individual basis, by an informed patient and his clinician, after weighing that patient’s particular risk factors.”
3. One Man at a Time — Resolving the PSA Controversy, by Mary McNaughton-Collins and Michael Barry. The authors suggest a modification of the draft recommendations.
- “We applaud the task force’s careful evidence review and synthesis of results from five screening trials.”
- “”The task force points out that no trial showed a decrease in overall mortality with the use of PSA-based screening through 11 years of follow-up and that all trials showed either a small or no benefit in prostate cancer– specific mortality. But who is to decide what constitutes a ‘small’ benefit and whether it outweighs the potential harms?”
- “[I]n the European trial, there was a significant absolute reduction in mortality related to prostate cancer of about 7 deaths per 10,000 men over a median of 9 years of follow-up. Such a reduction might be small in the eyes of some men, but larger in the eyes of others. It is also possible that a larger benefit might accrue with longer follow-up.”
- “Our perspective is that this evidence of a possible small but finite benefit from the largest trial would best support a grade C recommendation for men 55 to 69 years of age.”
A grade C recommendation would mean that
The USPSTF recommends against routinely providing the service. There may be considerations that support providing the service in an individual patient. There is at least moderate certainty that the net benefit is small. Offer/provide this service only if other considerations support offering or providing the service in an individual patient.
Thus, the third paper listed above roughly splits the difference between the first two. That makes it seem sensible to change the grade from D to C.
However, it is also possible that the USPSTF already considered the arguments made in these papers. I am not an expert USPSTF process in general or their work to date on the PSA test in particular. If it has considered the range of views and interpretations offered in these papers, then the arrival at a grade of D already reflects an attempt to distill them into a recommendation. On what grounds should we believe a different grade is a more sensible distillation? It’s still possible a grade of C is more reasonable than D, but I could not draw that conclusion from these papers alone. On the other hand, that’s not my job. It’ll be interesting to see if the USPSTF changes grade in light of public comment.
Acknowledgement: Thanks go to Paul Kelleher for his comments on a previous draft of this post.