This controversy has led to backlash against PSA screening, most notably the US Preventative Task Force (USPTF) recommending against PSA screening in 2012. Under this backdrop, rates of PSA screening in the US have been declining for several years, predating the change from the USPTF. The concern is the impact that this may have on early detection and whether these changes will lead to delayed diagnosis – especially increased rates of metastatic disease, which is currently incurable.
To begin to address this concern, Weiner et al, identified all men diagnosed with prostate cancer in the National Cancer Data Base between 2004–2013. This is a dataset that includes men diagnosed at 1,089 different health-care facilities in the United States. They found that relative to 2004, the incidence of men presenting with metastatic disease in 2013 was 72% higher, with the biggest rise after 2007. The rate of overall or high-risk prostate cancer did not change over the 9-year study. While it could be argued the higher incidence of metastasis was simply due to earlier detection from better imaging, the PSA at diagnosis of men with metastasis in 2013 was significantly higher than in 2004 arguing against a shift toward lower volume metastatic disease.
While invariably more work needs to be done including adjusting for differences in an aging population to assess metastatic rates (i.e. rates per 100,000 age-adjusted population) not just incidence, the work is significant in that it suggests, if confirmed in other studies, a dramatic increase in metastatic disease. Importantly, the upward trends started several years before 2012 and thus the change in USPTF stance on PSA screening in 2012 is not the sole cause of these shifts, but rather likely a gradual move away from PSA screening. Whether smarter screening (novel biomarkers, MRI, etc.) or less over-treatment (i.e. increasing role of active surveillance) to lower harms can reverse these trends remains to be seen.
Written by: Stephen Freedland, MD, Editor-in-Chief, Prostate Cancer and Prostatic Diseases, Cedars-Sinai Medical Center, Los Angeles, CA