Cutting PSA screening could triple metastatic prostate cancer cases
The study, published online July 30 in Cancer, suggested that PSA testing and early detection may prevent approximately 17,000 men each year from having advanced PC at diagnosis.
“Although there are trade-offs associated with the PSA test and many factors influence the disease outcome, our data clearly indicate that not doing the PSA test will result in many more men presenting with far advanced prostate cancer,” Edward Messing, MD, of the University of Rochester Medical Center in Rochester, N.Y., said in a release. “Almost all men with clinically apparent metastases at initial diagnosis will die from prostate cancer.”
Using data from the Surveillance, Epidemiology, and End Results (SEER) database, Messing and colleagues looked at the number of men who presented with advanced PC between 1983 and 1985, the years immediately before routine PSA testing was conducted, and estimated the number of cases that would be expected to occur from 2006 to 2008 in the absence of PSA testing. This was accomplished by multiplying each age-race-specific average annual incidence rate from the pre-PSA era by the number of corresponding men in the year 2008 and adding the products.
Overall, the ratio of expected metastatic PC cases without screening to the actual number observed in 2008 was 3.1, according to the authors. “If this ratio was applied to the total U.S. population in the year 2008, then the total number of men presenting with [metastatic] PC in that year would be equal to approximately 25,000 instead of the approximately 8,000 actually observed,” they wrote.
The findings of the analysis could provide support for critics of a recent U.S. Preventive Services Task Force recommendation that said PSA screening for prostate cancer should not be a component of routine care. Messing et al acknowledged the inconsistent results of prior PSA research, citing a European study which demonstrated a reduction in PC mortality associated with screening, and two North American studies that demonstrated no such benefit.
Messing and colleagues also reported that the absolute reduction in incidence of presenting with advanced PC increased with age until 85, but they clarified the age groups in their study represented age in a given year, not age at time of screening. As such, the authors could not definitively investigate the optimal age at which screening should begin.
“We believe that these estimates must be taken into consideration (bearing in mind the limitations of observational data) when public health policy-level recommendations are made regarding PSA screening,” concluded the authors.