Lower PSA Screening Rates Linked to Rise in Mets Prostate Cancer

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.

At 128 VA facilities, PSA screening rates fell from 47.2% in 2005 to 37% in 2019, while the incidence of metastatic prostate cancer increased from 5.2 per 100,000 to 7.9 per 100,000 men during that time .

The current study is “very important because it showed that we observed an increase in patients with late-stage prostate cancer in patient groups where screening was not recommended or not practiced,” said Jeff M. Michalski, MD, MBA, President – American Society for Radiation Oncology (ASTRO)-elect, at a press conference.

“This will likely result in increased mortality from prostate cancer in this patient population who have not had the opportunity to be screened,” added Michalski of Washington University School of Medicine in St. Louis, who was not involved with the research.

The study was presented at the ASTRO Annual Meeting on October 25 and published online on October 24 JAMA oncology.

PSA screening remains “controversial,” study author Brent S. Rose, MD, of the University of California, San Diego, said during the press conference.

PSA screening became widespread in the 1990s, but that changed after several randomized controlled trials failed to show consistent clinical benefit of PSA screening. A study conducted in Europe found a significant difference in mortality from prostate cancer at screening, while one in the US did not.

In 2012, the US Preventive Services Task Force (USPSTF) recommended PSA screening in healthy men of all ages.

But the debate about the value of PPE continues.

The result: “Physicians have very different views on the risks and benefits of prostate cancer screening,” said the study’s lead author, Dr. Alex K. Bryant, of the University of Michigan Rogel Cancer Center, Ann Arbor, in a press release.

To provide some real-world evidence, the researchers looked at PSA screening rates at all 128 VA facilities. This included annual PSA screening rates within the facility as well as rates of missed screening appointments. Between 2005 and 2019, the cohort grew from 4.7 million to 5.4 million males.

The researchers found that PSA screening rates fell from a peak of nearly 51% in 2008 to 37% in 2019, with the reductions being seen across all age and racial groups. Over the same period, the team observed a corresponding increase in long-term non-screening rates – men who missed screenings 3 years in a row. The long-term non-screening rate increased from a low of about 21% in 2009 to a high of 33% in 2019.

Notably, the incidence of metastatic prostate cancer increased from a low of 4.6 cases per 100,000 men in 2008 to 7.9 per 100,000 men in 2019, in large part due to an increase in incidence in men aged 55 and older.

Facilities with higher annual PSA screening rates had lower recurrence rates of metastatic prostate cancer. For every 10% increase in PSA screening rate, there was a corresponding 9% decrease in the incidence of metastatic prostate cancer 5 years later (incidence rate ratio [IRR]0.91; P < 0.001).

Conversely, facilities with lower annual screening rates had higher metastatic prostate cancer recurrence rates 5 years later (IRR, 1.10; P < 0.001). In addition, 5 years later, for every 10 percent increase in long-term PSA rate without screening, there was an 11 percent increase in the incidence of metastatic prostate cancer (IRR, 1.11; P = 0.01).

The authors noted several limitations of their study. The analysis is retrospective, and the veteran population may differ from the civilian population in terms of age, comorbidities, environmental exposures, and socioeconomic factors.

Overall, however, the results support PSA screening as a “beneficial intervention,” Rose said.

“I hope that this data … will give the USPTF an opportunity to revisit the recommendations, because along with the risk of overdiagnosis and overtreatment, there is also a risk of underdiagnosis and undertreatment,” Michalski noted.

The rationale for changing USPTF guidelines in 2012 was to “disadvise the use of PSA screening to detect prostate cancer in asymptomatic men,” he explained.

“We don’t want to go back to the day where everyone is offered screening in malls, in every doctor’s office, because there was this phenomenon that a lot of patients were diagnosed with cancer that wasn’t really life-threatening,” Michalski said Medscape Medical News.

But some men, such as those with a family history of the disease or from a certain ethnic or racial background, “are at higher risk of developing prostate cancer, so screening needs to be targeted,” he explained.

Marc B. Garnick, MD, who was not involved in the research, noted that the study represents a “very important contribution to the ongoing controversy about the value of PSA screening.”

Garnick of Harvard Medical School in Boston, Massachusetts Medscape Medical News that “the greater incidence of metastases associated with lower screening rates, particularly in older patients, should encourage further studies, preferably in randomized settings, to determine whether a change in our screening guidelines should be reconsidered.”

No funding for the study was reported. Rose has not disclosed any relevant financial relationships. Bryant has a relationship with the Boston Consulting Group. Other authors have numerous industry connections.

American Society for Radiation Oncology (ASTRO) Annual Meeting 2022: Abstract 298. Presented October 25, 2022.

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