Two studies show that fewer men have been screened for prostate cancer using the PSA test since 2012, when a federal panel advised against routine screenings. With doctors increasingly questioning the test's validity, that's a good thing. But the real key is whether reduction in PSA testing has led to a rise in late-stage or fatal prostate cancer.
The current JAMA published two articles and an editorial dissecting recent trends in prostate-specific antigen (PSA) testing among American men. The PSA test was introduced in the late 1980s in an attempt to use it as a reliable predictor of prostate cancer, but too many false positives and false negatives led many physicians to question its validity as a screening test. Moreover, the ramifications of false positives prostate biopsies and sometimes prostatectomies (removal of the gland) left many men impotent and/or incontinent.
In 2008, the federal panel charged with objective evaluations of clinical practices, the United States Preventive Services Task Forces, came to the conclusion that the evidence supporting a net benefit for routine annual PSA testing was flimsy. Not many MDs listened to the advice given at that time.
In 2012, after investigating new studies done since '08, the USPSTF issued a stronger advisory, for healthy men to steer clear of the test.
"The recommendation is against (emphasis added) prostate-specific antigen based screening for healthy men, asserting that there is moderate or high certainty that the service has no benefit or that the harms outweigh the benefits."
Officials discouraged the use of the test by issuing it a Grade-D rating. The D rating applies to men of all ages but does not apply to the use of PSA testing for monitoring patients after a prostate cancer diagnosis or treatment.
The researchers involved in the two JAMA studies sought to assess the trend in PSA testing since the second USPSTF report in 2012. Both articles came to the same conclusion.
The first, done by American Cancer Society authors, led by Ahmedin Jemal, DVM, PhD, found that "screening rates increased by 10 percent between 2005 and 2008 and then decreased by 18 percent between 2010 and 2013. The number of men 50 years and older diagnosed with prostate cancer nationwide declined from 213, ¯562 in 2011 to 180 ¯,043 in 2012, or 16 percent."
They concluded that "[b]oth the incidence of early-stage prostate cancer and rates of PSA screening have declined and coincide with 2012 USPSTF recommendation to omit PSA screening from routine primary care for men. Longer follow-up is needed to see whether these decreases are associated with trends in mortality."
The second JAMA study (in the format of a research letter) was done by a multi-center group, mostly from the Dana-Farber Cancer Institute in Boston, led by Jesse Sammon, DO. These researchers found that between 2010 and 2013, the PSA screening rate among their study population declined from 36 percent to 31 percent (they had no data on rates of prostate cancer).
An editorial in the same journal entitled "The Pendulum of Prostate Cancer Screening" by David F. Penson, the chairman of Urology at Vanderbilt University Medical Center, acknowledged that too much screening could do harm, but suggested that the pendulum had swung too far the other way. His position was that it would be better to screen smarter by testing most men less often and focusing more on those at high risk. He disputed the panel recommendation against any routine screening.
The key piece of information lacking at this time is the updated rate of late-stage and fatal prostate cancer since the reduced PSA screening took hold in 2012. If about the same number of deaths from prostate cancer is found, then the reduction in screening tests accomplished its goal: to reduce unnecessary procedures among men with indolent or non-existent cancer diagnosed by elevated PSA.
On the other hand, if there has been a significant bump in prostate cancer morbidity and mortality commensurate with the decline in screening PSAs, then the recommendations may well have to be re-visited. And the real outcome data won't be accumulated for some years, given that most prostate cancers, even those with a terminal outcome, do tend to grow fairly slowly.