Single PSA Screening Does Not Improve Prostate Cancer-Related Mortality
Recommendations about population-wide PSA screening are mixed, with some studies suggesting that the potential benefits of early diagnosis are outweighed by overtreatment.
A single prostate-specific antigen (PSA) screening may not improve the 10-year rate of prostate cancer–specific survival, though low-risk disease is more likely to be detected, according to research published in JAMA Oncology.1
Recommendations about population-wide PSA screening are mixed, with some studies suggesting that the potential benefits of early diagnosis are outweighed by overtreatment. No major study has, however, determined whether a single PSA screening is likely to benefit patients over a long follow-up period.
For this study (the Cluster Randomized Trial of PSA Testing for Prostate Cancer; CAP), researchers attempted to “determine the effects of a low-intensity, single invitation PSA test and standardized diagnostic pathway on prostate cancer–specific and all-cause mortality while minimizing overdetection and overtreatment.”
Of over 415,000 enrolled patients, 189,366 were randomly assigned to undergo a single PSA test (intervention group) and 219,439 were assigned to a control group. The mean age was 58.5 years vs 58.6 years in the intervention vs the control group, respectively; 3.6% vs 3.7% of patients had diabetes and 8% vs 7.8% of patients were obese.
Of patients assigned to the intervention group, 64,436 underwent PSA testing and had a valid result. Eleven percent of these patients had a PSA level between 3 ng/mL and 19.9 ng/mL; 85% of patients in this PSA range underwent biopsy.
The median follow-up was 10 years; during this period, 549 patients in the intervention group and 647 patients in the control group died of prostate cancer (rate ratio [RR] for deaths per 1000 person-years, 0.96; P = .5). More patients in the intervention group were, however, diagnosed with prostate cancer during follow-up (8054 vs 7853; RR, 1.19; P < .001).
Prostate cancers diagnosed in the intervention group were, furthermore, more likely to have a Gleason grade of 6 or lower.
The rate of all-cause mortality was also similar between the groups: at 10 years, 25,459 patients in the intervention group and 28,306 patients in the control group had died (RR, 0.99; P = .49).
The authors concluded that “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 under way, the findings do not support single PSA testing for population-based screening.”
- Martin RM, Donovan JL, Turner EL, et al. Effect of a low-intensity PSA-based screening intervention on prostate cancer mortality: the CAP randomized clinical trial. JAMA Oncol. 2018 Mar 6. doi: 10.1001/jama.2018.0154 [Epub ahead of print]