Screening healthy men for signs of prostate cancer does more harm than good, says a team of reseachers in Wednesday’s Journal of the American Medical Association.
That conclusion, which authors acknowledge runs against current trends in American medicine, is based on statistical probability analysis, which finds that, on average, prostate screening adds only a few days to a man’s life expectancy.
The risks of surgically removing the prostate, including sexual impotence and urinary incontinence, don’t justify the benefits on average, the analysis found.
Annual exams for prostate cancer for men older than 50 have been endorsed by the American Cancer Society and several medical specialty organizations even though many medical experts question their value.
The journal article is the latest to challenge claims by Cancer Society advocates, noting there is no convincing scientific proof that early detection and treatment of prostate cancer extends life.
“Our analysis shows that screening may marginally reduce prostatic cancer mortality for men between the ages of 50 and 70 years, but it suggests that the benefits of reduced prostatic cancer mortality are more than offset by the morbidity of prostatic cancer treatment,” said the report by Dr. Murray Krahn of the University of Toronto and colleagues.
“In the aggregate, we predict that screening will result in net harm rather than net health improvement.”
The analysis included tests for prostate cancer by digital rectal examination, use of a blood test that measures a substance called PSA-prostate-specific antigen-and use of ultrasound scanning.
The researchers said their analysis was hampered by the lack of reliable research on the comparative benefits of treating prostate cancer by surgically removing the gland, or exposing it to radiation or freezing it.
Until research is done to gauge the true benefits of screening and early treatment, probability analysis using existing information represents the best science can do, said Krahn, and that analysis rules against prostate screening.
An editorial accompanying Krahn’s study said that it won’t end the debate about screening and treatment.
Dr. Gerald Chodak, a University of Chicago urologist, said in the editorial that rather than abandon screening altogether, physicians should advise patients of the potential benefits and risks of screening and treatment and leave the decisions up to them.
The National Institutes of Health is sponsoring a study intended to resolve the issue by screening thousands of men for prostate cancer and comparing their outcomes to that of thousands of others who aren’t screened.
The problem, said Chodak, is that prostate screening programs in community hospitals have become so popular that large numbers of men in the study who aren’t supposed to be screened will get the tests on their own, tainting study results.
In the absence of controlled scientific studies to settle prostate cancer questions, many fear that advocates of various views now resemble hucksters.
“Marketing distributes promises, sometimes based upon preliminary and tenuous data, to the consumer and the physician, thereby creating demand and sales,” wrote Dr. Paul Schellhammer of Eastern Virginia Medical School in the August issue of Urology.
Dr. Peter Littrup of Wayne State University put it more bluntly: “Radical prostatectomy, radiation therapy, and cryotherapy. . . the butcher, the baker and the ice-cube maker. . . merchants in the casbah of prostate cancer therapy, singing the praises of their wares.”
