Tuesday, June 05, 2012

[P]retty [S]orry [A]nalysis

There are interesting, legitimate, and important scientific and clinical issues under debate with regard to the efficacy of PSA screening.  The national group that looks at such matters is the US Preventive Services Task Force, which makes recommendations about the effectiveness of specific clinical preventive services for patients without related signs or symptoms.  Here are excerpts from its latest draft recommendation:

The U.S. Preventive Services Task Force (USPSTF) recommends against prostate-specific antigen (PSA)-based screening for prostate cancer. This recommendation applies to men in the U.S. population that do not have symptoms that are highly suspicious for prostate cancer, regardless of age, race, or family history. The Task Force did not evaluate the use of the PSA test as part of a diagnostic strategy in men with symptoms that are highly suspicious for prostate cancer. This recommendation also does not consider the use of the PSA test for surveillance after diagnosis and/or treatment of prostate cancer.

The USPSTF recognizes that clinical decisions involve more considerations than evidence alone. Clinicians should understand the evidence but individualize decisionmaking to the specific patient or situation.

Now, along comes an article from Reuters Health Information that turns the process of scientific discourse on its head, first with an inflammatory headline:  "For Some, Prostate CA Screening Can Be Difference Between Life and Death."  Then a summary of a talk from the 107th Annual Scientific Meeting of the American Urological Association is presented.  Here are excerpts from the article:

Men of lower socioeconomic status and those from third world countries are a subset of patients who do need prostate-specific antigen screening, researchers said last week. . . .  That's because these men often present with advanced, metastatic prostate cancer, Dr. Brian K. McNeil, from SUNY Downstate Medical Center, Brooklyn, NY, told Reuters Health in an interview.

"Considering the recent controversies regarding PSA screening, including the recent US Preventive Task Force recommendation against screening, we decided to study those patients in our population who presented to Downstate with metastatic prostate cancer to identify those who would suffer if PSA screening was eliminated," Dr. McNeil said.

He and his team searched a prospectively maintained androgen deprivation therapy database from their inner city hospital and identified 148 men who presented with metastatic prostate cancer.

[Details of clinical metrics for these men are then presented.]

"The scary thing for me is that the US Preventive Service Task Force recommendations could discourage some men from getting screened who would benefit from screening. With the patients in our study, who knows what would have happened if they were screened and the cancer was detected much earlier," Dr. McNeil said.

Huh?  The entire article is all about how these men presented with advanced disease and all about the advanced disease. There is not one further word about how the researchers determined that "men of lower socioeconomic class and those from third world countries" were the ones who needed the PSA test.  We never learn how they decided that this group is somehow distinguishable in some way that would warrant a different conclusion from that reached by the USPSTF -- particularly the part that said regardless of age, race, or family history.

Maybe I shouldn't judge from the article alone.  Maybe the scientific paper has a cogent hypothesis that is supported by the data.  But, as presented here -- and picked up by several other publications -- this seems like a pretty sorry analysis.

1 comment:

Sloan said...

Your analysis is spot on, especially when the creator of the PSA has said repeatedly that the test was never demonstrated to be reliable enough to be used as a screening tool for all men over 40. Unfortunately, in a time when the general population is moving further and further away from trusting scientific analysis to trusting anecdotal “evidence” instead, it is worrisome that physicians are also moving toward anecdotal evidence that supports the “art” of medicine. I pray that a new Age of Enlightenment will emerge from the current Dark Ages we find ourselves in. Your calling urologists to task is welcomed as a voice in the empirical wilderness.