P.S.A., Prostate Cancer, and the NYT

The NYT and WashPo recently published the results of a review done by a task force on the value of P.S.A. testing. (P.S.A. is a protein --Prostatic Specific Antigen--made by the prostate that gets into the bloodstream depending on number of blood vessels, their permeability and age. It rises in many instances of prostate cancer, as well as other conditions that increase vasculature and vessel permeability.)The report is astonishing in a number of ways and offers remarkable insights into problems facing the United States and its fragile relationship with science.

The task force, The United States Preventive Services Task Force, is an independent panel of experts in prevention and primary care appointed by the Department of Health and Human Services. They offer opinions on medical practice in the United States. While these positions are unsolicited, they often determine the approach taken by Medicare with regard to standards in health care management and, significantly, payment for testing. (A few years ago the task force determined that mammograms should been done only every two years rather than the traditional one year. The limits of funding followed.) In this particular task force study, the complications of therapy for the prostate cancers discovered was seen as unjustified when compared to the improvement in survival rate, which was seen as slight. In essence, P.S.A. elevation was seen to result in complications from biopsies and eventually complication from therapy when the biopsy was positive and no advantage in life expectancy was seen over a ten year period.

Several of the studies were particularly interesting as they compared tested and untested groups rather than diseased and healthy groups--they used testing as a proxy for disease found. So the Scandinavian study compared groups tested for P.S.A. against those not tested for P.S.A. and compared their life expectancy over seven to ten years. Men declining biopsy as well as those with negative biopsies were included in the tested group. As elevated P.S.A. is associated with negative biopsy 70% of the time, the tested group give a muted idea of the disease. But most complications of biopsy--like blood in the semen at 50%--while harmless are reported as serious complications.

Another factor not considered is the target population of biopsy. Most agree that clinical prostate cancer, that is cancer that is symptomatic and/or can be appreciated on examination, does not limit the life expectancy in men over the age of 70 in most cases but does in those men under 70. However, P.S.A. elevation--when associated with prostate cancer--precedes clinical findings by 5 to 7 years. Thus the target group for physicians treating prostate cancer is men under the age of 65 or so. Another group is those with rapidly growing disease in the generally low risk populations as P.S.A. changes often reflect that. Targeting these groups is more than reasonable; in a civilized society that understands the implication of illness and feels a responsibility towards its victims, it is obligatory. Another important factor is the development of symptoms which can be decreased or eliminated by early detection; thus survival rate does not tell the whole story.

What is particularly galling about these haphazard investigations and reviews is that they are done by seemingly reasonable people, people who should know the limits of their studies and the difficulties inherent in making good scientific generalities. Perhaps the makeup of the task force is illuminating: There is no one on the task force collecting information on P.S.A. and prostate cancer who clinically evaluates or treats either.

In essence, for the sake of unbiased neutrality, expertise and knowledge on the task force were screened out.