Baseline prostate inflammation is associated with a reduced risk of prostate cancer in men undergoing repeat prostate biopsy: results from the REDUCE study.

Background: The current study was performed to evaluate whether baseline acute and chronic prostate inflammation among men with an initial negative biopsy for prostate cancer (PCa) increased the risk of subsequent PCa detection in a clinical trial with systematic biopsies.

Methods: A retrospective analysis was performed of 6238 men aged 50 years to 75 years with prostate-specific antigen levels between 2.5 ng/mL and 10 ng/mL and a prior negative biopsy in the REduction by DUtasteride of PCa Events study who completed a 2-year biopsy. PCa, acute prostate inflammation, and chronic prostate inflammation were assessed by central review. The association between inflammation in baseline prostate biopsies and positive 2-year and 4-year repeat biopsies was evaluated with the chi-square test and logistic regression analysis adjusting for baseline covariates.

Results: Acute and chronic inflammation and both were detected in 46 baseline biopsies (1%), 3931 baseline biopsies (63%), and 892 baseline biopsies (14%), respectively. Acute and chronic inflammation were found to be significantly associated with each other (P<.001). Acute inflammation at baseline biopsy was associated with younger age, lower prostate-specific antigen levels, and a smaller prostate (all P<.01), whereas chronic inflammation was associated with older age and larger prostate glands (all P<0.01). At the 2-year biopsy, the prevalence of PCa was 14% (N=900 patients). On univariable and multivariable analysis, both acute and chronic inflammation were found to be significantly associated with a lower PCa risk (acute univariable: odds ratio [OR], 0.65 [P<.001] and multivariable: OR, 0.75 [P=.012] and chronic univariable: OR, 0.61 [P<.001] and multivariable: OR, 0.65 [P<.001]). At the time of 4-year biopsy, only acute inflammation was found to be associated with a lower PCa risk.

Conclusions: Baseline acute and chronic inflammation were both found to be independently associated with a lower PCa risk. From a clinical standpoint, inflammation in negative biopsies for PCa may lower the risk of subsequent PCa detection.