1. PSA screening was associated with a reduction in risk for death from prostate cancer.
2. No differences in the effects of PSA screening were found between the European Randomized Study of Screening for Prostate Cancer (ERSPC) and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO).
Evidence Rating Level: 2 (Good)
Study Rundown: Controversy exists regarding the utility of prostate-specific antigen (PSA) screening. In 2012, the U.S. Preventive Services Task Force stated that screening has a very low impact in terms of preventing death from prostate cancer. The Task Force utilized two studies, ERSPC and PLCO, to draw its conclusions. However, differences exist between these studies; the ERSPC concluded that screening had a 21% reduction in prostate cancer mortality, while the PLCO study found no difference in mortality between the control and intervention groups. As these studies differed significantly in terms of their design and practice settings, the authors of this paper aimed to formally test whether the effects of screening on prostate cancer mortality compared to no screening intervention different between the ERSPC and PLCO using Cox regression models. This study has several limitations. Mainly, the authors did not explicitly account for differences between trials with regards to cancer case characteristics and primary treatments. Overall, they found that with re-analysis of the evidence, PSA screening significantly reduces the risk of death from prostate cancer.
In-Depth [retrospective cohort]: The authors of this study compared two randomized controlled trials using Cox regression models, which adjusted for age and trial. Two analyses were performed: a traditional statistical analysis and an extended analysis that incorporated the mean lead time (MLT), which reflects the average time by which diagnosis is advanced by screening compared to the date of diagnosis without screening. Generally, the authors found that PSA screening reduced the risk of prostate cancer mortality. For example, they estimated that screening reduced risk for prostate cancer death by 7% to 9% per year of MLT. The ERSPC intervention group therefore had an approximate risk reduction of 27% to 32% and the PLCO had an approximate risk reduction of 25% to 31% compared to the control groups. Furthermore, it was observed that benefit of PSA screening increased with MLT (P = 0.0027 to 0.0032).
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