Discussion of USPSTF recommendation continues apace


Many readers of this blog will enjoy reviewing the editorial commentary in today’s issue of the influential USA Today, entitled “Skipping prostate test can kill“.

In the interests of “fair balance” we should note that the same issue of USA Today also carries another iteration of the OpEd by Dr. Virginia Moyer, the chairwoman of the USPSTF, entitled “Make informed decisions on PSA“.

The key point being made by USA Today is critical to the entire discussion about the value of the PSA test as a tool to assess risk for prostate cancer. What is true on average for an entire population is most certainly not true for a significant number of individuals in that population. As individual humans, we make decisions about and for ourselves as individuals; from that perspective, the findings of the USPSTF are intellectually accurate and interesting … but they may be completely irrelevant.

7 Responses

  1. It would seem that the quote from Dr. Spock in Star Trek says it all, “The good of the many outweighs the good of the few or the one”.

    Society as a whole is worse off by routinely screening for prostate cancer but some individuals will benefit.

  2. Dr. Moyer in her reply continues to cite some statistics on benefits versus harms that give a misleading impression. Specifically, she says that for every 1,000 men screened, at most 1 life will be saved, and 40 men will suffer erectile dysfunction or urinary incontinence.

    The latter statistic of 40 is only correct if none of the men who are unscreened would, during the following 10 years, be diagnosed or treated for prostate cancer. But screening doesn’t change detection and treatment of prostate cancer from “zero” to some positive level; it changes diagnosis and treatment of prostate cancer from one level to a somewhat higher level.

    If one compares the difference in diagnosis and treatment between the screening and control group, for every life saved due to screening, there might be 7 to 13 men who suffer from erectile dysfunction or urinary incontinence. This is obviously a difficult trade-off to deal with, about which men may differ in their opinions. But a ratio of harms to life saved of 7 to 1 is obviously quite different from a ratio of 40 to 1.

  3. I know I am beating a dead horse, but I can’t understand why so many people do not recognize the inherent flaw in the panel’s logical reasoning. Dr. Moyer states, as quoted in the above-cited editorial:

    “At best, there is a very small potential benefit from the PSA test and there are substantial known harms.”

    Clearly and indisputably, “substantial known harms” will follow after the PSA test and further diagnostic tests or treatment are prescribed, but the only known harms from the test itself are a few extra seconds of blood drawn and the additional lab cost for the report (excluding some anxiety and risk of infection). The PSA test itself is as harmful as the blood test for potassium, bilirubin, or creatinine.

    The panel’s logic is: If a PSA test is ordered, then there will be a biopsy and/or treatment. I submit it is the medical professional that has the ultimate responsibility, in consultation with the patient, to decide what additional diagnostic tests and treatment, if any, should follow after the PSA test results are reported. The Panel’s “D” grade, if it is justified, is more appropriately directed to the medical professional for allegedly failing to understand the inherent limitations of the PSA test results, and for failing to educate the patient. The greatest harms following the PSA test are from the patient’s undergoing biopsies and treatment when none may be warranted. But is that the test’s fault, or the fault of the doctor whom the Panel apparently believes is not educated, trained, or informed enough to know what to do with the results. This explains the urologists’ rage. The Panel has announced, in effect, that urologists have no idea how to interpret or use the PSA test results, or they are misinformed of the results of their past recommendations to biopsy and treat. And this all may be true (and certainly is true in many [most?] cases based upon the Panel’s “evidence”), but don’t blame the messenger.

    Shouldn’t the panel’s recommendation be: “There is a potential for a life-saving benefit from the PSA test, but in most cases, due to the substantial known harms of biopsies and treatment and the slow-growing nature of prostate cancer, the medical professional should not order a biopsy or prescribe treatment without first explaining to the patient the relative risks and benefits of no diagnostics or treatment.”

    Sitemaster, thank you for letting me vent. I feel much better now!

  4. WHY NOT MEASURE BOYS HEIGHT AT AGE 10 TO ASSESS MALE ADULT HEIGHT – WOULD BE LIKE USPSTF RELIANCE ON PREMATURE DATA

    Returning to the height analogy raised by Dr. Reich in the “USA Today” editorial, if anyone wanted to spend money on assessing height of male adults in the US by measuring height of boys at age 10, everyone would consider them nutty. Yet that is similar to what the task force has done. In her op-ed reply, Dr. Virginia Moyer, chairman of the USPSTF, emphasizes that “at most, one man in 1,000 screened will avoid a prostate cancer death through 10 years. The best and largest study in the U.S. found that no deaths were avoided.”

    Well, duh! I see it that way too, but it is completely irrelevant because the 10 years of follow-up from the time of study enrollment is simply far too short a follow-up period to assess the impact of screening when it is well established that survival from date of diagnosis is virtually 100% for low- and intermediate-risk men and about 95% for high-risk men, a far smaller group.

    We are blessed with a disease that now is associated with the longest survival for any of the major cancers, and my hunch is that most of the relatively few deaths from prostate cancer tallied in the PLCO study are among men with extremely high-risk prostate cancer (small cell, endometrial, etc.), cases where early detection due to screening would likely not have made much of a difference during the reported period of the PLCO study.

    However, we should get a better idea of the impact of screening during the second decade of follow-up, especially if counted from the data of diagnosis rather than from the time the patient was enrolled in the PLCO trial. There are other problems with the PLCO study that need handling, such as counting men who were supposed to be screened but were not (the “intent to screen” group), and vice versa, but that can be addressed. What cannot be addressed until substantially more time passes is premature follow-up.

    The USPSTF relied on premature results — not just slightly premature, but too premature to support its conclusions at all. The USPSTF blundered in handling the science. It is imperative that we don’t let them off the hook!

  5. “USA TODAY” EDITORIAL — GOOD POINTS, BUT SEEMS UNAWARE OF “ACTIVE SURVEILLANCE”

    The editorial of this influential paper mentions “watchful waiting” instead of “active surveillance.” I take that as a sign that the editors do not appreciate the profound difference between the two, a distinction that also seems mainly lost on the USPSTF.

    I’m thinking the Task Force might have taken a reasonable approach if it had understood the role of active surveillance.

    We in the prostate cancer community clearly have a lot more work to do.

  6. Dear Jim:

    I think I have to tell you that (in my humble opinion) you can hardly blame the USPSTF for making decisions based on data that are not mature when it was the PLCO study coordinators who (a) decided to publish these data early and (b) packaged those data badly by — as you carefully point out — using date of enrollment in the trial as a baseline as opposed to date of diagnosis. I can argue strongly that if neither the PLCO data nor the ERSPC data had been published unjustifiably early, we wouldn’t be having the current conversation at all. “Garbage in, garbage out” is hardly a new problem in the world of science and medicine!

  7. Jim:

    I can assure you that the USPSTF most certainly understood (a) the potential role of active surveillance and (b) the difference between active surveillance and watchful waiting. While they did not say this explictly, I am also quite convinced that they had little to no faith in the willingness of either the general urology community or most newly diagnosed patients to actually apply the principles of active surveillance — even as currently outlined in the NCCN guidelines (which I would consider to be conservative).

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