SAN ANTONIO — Veterans Administration (VA) medical centers with lower prostate-specific antigen (PSA) screening rates reported higher rates of metastatic prostate cancer, a recent retrospective analysis found.
Across 128 VA facilities, PSA screening rates fell from 47.2% in 2005 to 37% in 2019, while metastatic prostate cancer incidence increased from 5.2 per 100,000 to 7.9 per 100,000 men in that time.
The current study is “very important because it showed that in groups of patients where screening was not encouraged or not practiced, we saw an increase in patients presenting with late stages of prostate cancer,” said Jeff M. Michalski, MD, MBA, president-elect of the American Society for Radiation Oncology (ASTRO), at a press briefing.
“This will likely lead to increased prostate cancer mortality in this population of patients who were not given the opportunity to be screened,” added Michalski, of Washington University School of Medicine in St. Louis, who was not involved in the research.
The study was presented on October 25 at ASTRO’s annual meeting and was published online October 24 in JAMA Oncology.
PSA screening remains “controversial,” study author Brent S. Rose, MD, of the University of California, San Diego, said during the press briefing.
PSA screening became widespread in the 1990s, but that changed after several randomized controlled trials failed to show a consistent clinical benefit for PSA screening. One trial conducted in Europe found a significant difference in prostate cancer mortality with screening, while one in the US did not.
In 2012, the US Preventive Services Task Force (USPSTF) recommended against PSA screening among healthy men of any age.
But the debate regarding the value of PSA has continued.
The result: “Physicians have very different feelings on the risks and benefits of prostate cancer screening,” lead study author Alex K. Bryant, MD, of the University of Michigan Rogel Cancer Center, Ann Arbor, said in a press release.
To offer some real-world evidence, the researchers studied PSA screening rates at all 128 VA facilities. They included yearly within-facility PSA screening rates as well as rates of missed screening appointments. Between 2005 and 2019, the cohort increased from 4.7 million to 5.4 million men.
The researchers found that PSA screening rates decreased from a high of nearly 51% in 2008 to 37% in 2019, with reductions seen across all age and race groups. Over the same period, the team observed a corresponding increase in the rates of long-term nonscreening — men who missed screenings 3 years in a row. The long-term nonscreening rate increased from a low of about 21% in 2009 to a high of 33% in 2019.
Notably, the incidence of metastatic prostate cancer rose from a low of 4.6 cases per 100,000 men in 2008 to 7.9 per 100,000 men in 2019, driven in large part by an increase in incidence among men aged 55 and over.
Facilities with higher yearly PSA screening rates had lower subsequent rates of metastatic prostate cancer. For every 10% increase in the PSA screening rate, there was a corresponding 9% decrease in metastatic prostate cancer incidence 5 years later (incidence rate ratio [IRR], 0.91; P < .001).
Conversely, facilities with lower yearly screening rates had higher subsequent rates of metastatic prostate cancer 5 years later (IRR, 1.10; P < .001). In addition, for every 10% increase in the long-term nonscreening PSA rate, there was an 11% increase in the incidence of metastatic prostate cancer 5 years later (IRR, 1.11; P = .01).
The authors noted several limitations to their study. The analysis is retrospective, and the veteran population may differ from the civilian populations in age, comorbidities, environmental exposures, and socioeconomic factors.
However, overall, the findings support PSA screening as a “beneficial intervention,” Rose said.
“I hope this data…will give an opportunity for the USPTF to reexamine the recommendations because, while there is this risk of overdiagnosis and overtreatment, there’s also a risk of underdiagnosis and undertreatment,” Michalski noted.
The rationale for the change in USPTF guidelines in 2012 was to “discourage the use of PSA screening to detect prostate cancer in asymptomatic men,” he explained.
“We don’t want to come back to the day where everyone is offered screening in shopping malls, in every doctor’s office, because there was this phenomenon that many patients were being diagnosed with cancers that were not really life threatening,” Michalski told Medscape Medical News.
But some men, such as those with a family history of the disease or from certain ethnic or racial backgrounds, “have a higher risk of developing prostate cancer, so screening has to be targeted,” he explained.
Marc B. Garnick, MD, who was not involved in the research, noted that the study is a “very important contribution to the continuing controversy regarding the value of PSA screening.”
Garnick, of Harvard Medical School, Boston, Massachusetts, told Medscape Medical News that “the greater incidence of metastatic disease associated with lessened screening rates, especially in older patients, should encourage further studies, preferably in randomized settings, to determine whether an alteration in our screening policies should be revisited.”
No funding for the study has been reported. Rose has disclosed no relevant financial relationships. Bryant has a relationship with Boston Consulting Group. Other authors have numerous relationships with industry.
American Society for Radiation Oncology (ASTRO) 2022 Annual Meeting: Abstract 298. Presented October 25, 2022.