The prostate specific antigen (PSA) test to detect early prostate cancer has been publicized with unbounded enthusiasm ever since it was introduced in the late 1970′s. In the last several years, however, the use of the test has become increasingly controversial. With a death rate of 25 per 100,000 men, prostate cancer is still the second leading cause of cancer deaths among men, but well behind lung at 70/100,000. Yet many forms of prostate cancer remain dormant for decades. For example, at autopsy, prostate cancer is found incidentally (in those dying of other causes) in 30% of men of 50, rising to 55% over 80 and almost 100% of men over 90. Moreover, the 5-year survival rate, the percentage of men who do not die from prostate cancer within 5 years after the cancer is found is 100%, and the relative 10 and 15 year survivals are 91% and 76% respectively. Since current treatments, outside of “watchful waiting” and hormone therapy, consist of radical surgery and radiation, both accompanied by high rates of complications, the incidental discovery of early prostate cancer cannot be taken lightly.
Two recent landmark studies have just been published in the New England Journal of Medicine, one involving more than 76,000 men. This U.S. Government-funded study found that the PSA screening test did not reduce the death toll from prostate cancer in the first decade. The second study, a European trial involving more than 162,000 men, did report fewer deaths among those tested, but the reduction was relatively modest, and some experts said the study design made estimates of reduction difficult to interpret. The European study did confirm what has been known for years, that large numbers of those screened suffered needless and often harmful treatment. Among men undergoing radical prostate surgery, 55%-76% suffer severe erection problems and impotence, and up to 50% experience urinary incontinence for over a year or longer following operation. Reliable figures on persistence of impotence are difficult to find, but a significant number of these men had permanent loss of sexual function. Different types of radiation treatment also resulted in erectile dysfunction and urinary incontinence, but the complication rates tend to be lower.
Because of the uncertainty resulting from these and previous studies, many major medical groups have stopped recommending routine PSA screening. The U.S. Preventive Services Task Force which sets federal policy on preventive health care, last year recommended doctors stop testing elderly men, and concluded that it was unclear if screening was worthwhile for younger men. In the European study of men between 55 and 69, the figures at best mean about 10,000 men would have to be screened for 10 years to prevent seven deaths from prostate cancer. Expressed another way, 1410 men would need to be screened and 48 would have to be treated to prevent one death.
Because of increasing evidence of ineffectiveness and unforeseen consequences of PSA screening, many patients are now given helpful information about the test and can elect to forego it. This is not the option, however, if a man gets a freebie at the local shopping mall. Sadly, the enthusiasm about finding prostate cancer “early” continues to trump evidence that doing so may indeed cause more harm than good. PSA screening will probably be with us for many years into the future.