Study: PSA Screening for PCa and Risk of Overt Metastatic Disease at Presentation
The upshot of PSA screening demonstrated in new study
August 01, 2012 -- A new study gives important counterbalance to the recent recommendation by the U.S. Preventative Services Task Force (USPSTF) against routine prostate-specific antigen (PSA) testing for prostate cancer. The results of the new study, published online yesterday in the journal Cancer, found that if PSA testing (in widespread use currently) were widely rolled back, three times the number of men would be diagnosed with advanced prostate cancer that had spread outside the organ and is much more difficult to treat.
The study showed steep declines in the prevalence of men diagnosed with metastatic prostate cancer around the time PSA testing came into widespread use in the United States in the early 1990s; this was especially pronounced in men over the age of 60.
Currently with widespread PSA testing, some 8,000 U.S. men are diagnosed each year with metastatic prostate cancer; the study calculated that number would be 25,000 if not for PSA testing.
The pitfall of widespread testing is over diagnosis of prostate cancers that lack the potential to shorten a man’s life; the benefit is catching the disease early, before it has time to spread in men for whom that would occur. The Catch-22 is that currently there is no definitive way to determine which man diagnosed with early prostate cancer will go on to metastatic disease and which can live comfortable with his non-lethal tumor.
The senior author on the study, Dr. Edward M. Messing, was quoted in HealthDay as saying that the USPSTF recommendation on PSA testing this year, “wasn’t a brilliant conclusion.” Dr. Messing won a PCF Competitive Award in 1993 in the amount of $100,000 at the University of Rochester.
Dr. Stuart Holden, director of the Louis Warschaw Prostate Cancer Center at Cedars-Sinai Medical Center and the medical director of the Prostate Cancer Foundation, who was not involved in the study, said, “It’s definitely true that wholesale screening using PSA leads to over detection and over treatment, but within that group of men there is a subset of patients—and not an insignificant subset, as shown by this study—that are surely benefited by PSA screening and treatment.”
Dr. Holden also said that he and many other urologists who practiced medicine in the pre-PSA era, witnessed changes that are undeniably positive in the PSA era—meaning doctors see a lot fewer men diagnosed with late-stage prostate cancer that is likely to significantly shorten their lifespans. “It strikes me as horrifying to think someone would make a recommendation which might take us back to that era again,” he said.
In fact, he said, China is now in a pre-PSA era, where much of the prostate cancer doctors see in that country has progressed to the advanced metastatic stage that is often lethal. Ultimately the answer, both in the U.S. and around the world, will be better science that can, with good accuracy, determine at an early state of diagnosis, which prostate cancer is destined to become lethal and which is so slow-growing that treatment can be avoided.