Effect of Single PSA-Based Screening on Prostate Cancer Mortality
In the UK-based CAP trial reported in JAMA, Martin et al found that a single prostate-specific antigen (PSA) screening was not associated with better 10-year prostate cancer-specific survival vs the standard practice of no screening. Screening was associated with greater detection of prostate cancer, particularly low-risk cancers.
Study Details
The trial included 408,825 men aged 50 to 69 years in 573 UK primary care practices. Practices were randomized between 2001 and 2009 to have patients receive an invitation to attend a PSA testing clinic and receive a single PSA test (n = 189,386) or to the standard practice of no screening (n = 219,439). Patient follow-up ended in March 2016.
In the intervention group, 75,707 (40%) attended the PSA testing clinic and 67,313 (36%) underwent PSA testing. Of 64,436 with test results, 6,857 (11%) had a PSA level between 3 ng/mL and 19.9 ng/mL; of these, 5,850 (85%) underwent prostate biopsy.
Survival and Incidence
After median follow-up of 10 years, death from prostate cancer had occurred in 549 patients (0.30 per 1,000 person-years) in the intervention group vs 647 (0.31 per 1,000 person-years) in the control group (rate difference = −0.013 per 1,000 person-years; rate ratio [RR] = 0.96, P = .50). Prostate cancer was diagnosed in 8,054 patients (4.3%) in the intervention group vs 7,853 (3.6%) in the control group (RR = 1.19, P < .001). A higher incidence of prostate tumors with Gleason grade ≤ 6 was found in the screening group (3,263 = 1.7% vs 2,440 = 1.1%), representing a difference of 6.11 per 100 patients (P < .001). In analysis of all-cause mortality, there were 25,459 deaths in the screening group vs 28,306 in the control group (RR = 0.99, P = .49).
The investigators concluded, “Among practices randomized to a single PSA screening intervention vs standard practice without screening, there was no significant difference in prostate cancer mortality after a median follow-up of 10 years, but the detection of low-risk prostate cancer cases increased. Although longer-term follow-up is underway, the findings do not support single PSA testing for population-based screening.”
The study was funded by Cancer Research UK and UK Department of Health, National Institute of Health Research.
Richard M. Martin, PhD, of the University of Bristol, is the corresponding author for the JAMA article.
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