Objectives: The efficacy of screening for prostate cancer (PCa) with digital rectal examination (DRE) and prostate-specific antigen (PSA) measurement has not been proved in randomized clinical trials. In an earlier case-control study, we found that DRE might reduce PCa mortality. The present case-control study assessed the association between PSA and DRE testing and PCa mortality.
Methods: The case subjects included 74 Olmsted County residents who had died from 1992 to 2005 with PCa as the underlying cause of death. From 1 to 3 community control subjects (alive at time of case subject's death) were matched to each case subject. The medical records were reviewed to identify DREs and PSA determinations performed 0 to 5 years before the date the case was diagnosed (index date). Tests performed in the absence of symptoms were considered to be "screening tests." Conditional logistic regression analysis was used to estimate the odds ratios and 95% confidence intervals for the association of screening (defined in multiple ways) and PCa mortality.
Results: From 1 to 5 years before the index date, control subjects were more likely than case subjects to have undergone a previous screening PSA test or DRE (81.3% versus 60.8%, P = 0.0005). The unadjusted odds ratio associated with a previous screening PSA test or DRE was 0.34 (95% confidence interval 0.18 to 0.63), and the odds ratio adjusted for potential confounders was 0.35 (95% confidence interval 0.17 to 0.71). PSA testing was frequently done in conjunction with DRE, making evaluation of the individual effects difficult.
Conclusions: The results of this case-control study suggest a potential benefit of screening by PSA testing and/or DRE on PCa mortality.