PSA Testing Linked to Reduced Mortality

Prostate-specific antigen (PSA) testing was shown to significantly reduce mortality among men, but the test had no effect on all-cause mortality, according to a study published in the New England Journal of Medicine.

In recent months, the benefits of PSA testing have been heavily debated, especially in the United States in light of a recommendation by the US Preventive Services Task Force against using PSA screening for prostate cancer among all age groups.

This new study, based on results from the European Randomized Study of Screening for Prostate Cancer, suggests that a benefit to patients with prostate cancer exists, but the net gain of survival is limited.

The multicenter study recruited 186,160 men between the ages of 50 and 74 at the time of enrollment across 8 countries, with 162,388 men comprising a core group of men between the ages of 55 and 69. These men were either randomly assigned to receive PSA-based screening or not offered such screening, with the primary outcome of the study being mortality from prostate cancer. The median follow-up period was 11 years in the core age group.

Among the patients in the core age group, the relative reduction in risk of death from prostate cancer in those who received PSA-based screening was 21% (95% CI, 0.68-0.91; P = .001) and 29% when the study’s authors adjusted for selection bias and noncompliance. The authors reported that based on the study results, the absolute reduction in mortality was 0.10 deaths per 1000 person-years. During the tenth and eleventh follow-up years, the death from prostate cancer rate ratio was 0.62 (95% CI, 0.45-0.85; P = .003).

However, between the 2 study groups, overall mortality was roughly the same, with 18.2 deaths per 1000 person-years in patients in the screening group and 18.5 months per 1000 person-years in patients in the control group (rate ratio .99; 95% CI, 0.97-1.01).

“[T]he reduction in prostate-cancer mortality needs to be balanced against the disadvantages of early detection of prostate cancer, with the proportion of overdiagnosis estimated to be approximately 5% of screening-detected cancers,” the authors of the study wrote. They noted that an evaluation of how quality of life was affected during the study is pending.

Anthony B. Miller, MD

The authors said that despite relative and absolute risk being determined across a very large cohort of patients, they were not going to make any recommendations before obtaining more information of the benefits and adverse effects related to screening as well as cost-effectiveness.

In an editorial accompanying the study, Anthony B. Miller, MD, professor at the Dalla Lana School of Public Health at the University of Toronto, noted that the study had numerous limitations compared to the Prostate, Lung, Colorectal, and Ovarian (PLCO) screening trial done in the United States, including 4 years passing in between screenings (except for Sweden, which invited participants back every 2 years) as opposed to annual screenings in the PLCO trial, a lower cutoff for positive PSA than the US study, and increased background screening in the US study compared to the European study.

“[B]efore accepting these results to guide policy, we need further clarification as to what actually happened in the trial, especially with respect to treatment, and confirmation that the two study groups were balanced,” Miller wrote.