Both acute and chronic inflammation are associated with less perineural invasion in men with prostate cancer on repeat biopsy

ObjectivesTo evaluate the association between acute and chronic inflammation with the presence of perineural invasion (PNI) in prostate biopsies positive for prostate cancer (PCa). Material and MethodsWe conducted a retrospective analysis of 1 399 prostate biopsies positive for PCa in the Reduction by Dutasteride of PCa Events (REDUCE) study. PCa, acute and chronic prostate inflammation and PNI were assessed by central pathology review. The association between acute and chronic inflammation with PNI was evaluated using chi-squared and Kruskal-Wallis tests, and logistic regression adjusting for clinicopathological and biochemical variables. ResultsThe presence of PNI was identified in 133 biopsies (9.5%). In all, 267 biopsies (19.1%) had acute inflammation, 1 038 (74.2%) had chronic inflammation, and 255 (18.2%) had both. The presence of both acute and chronic inflammation had a mutual association (P < 0.001). Chronic inflammation was associated with a lower Gleason score (P = 0.009) and lower tumour volume (P < 0.001), while acute inflammation was associated with lower Gleason score (P = 0.04), lower tumour volume (P = 0.004) and higher prostate-specific antigen levels (P = 0.05). In both univariable and multivariable analyses, chronic prostate inflammation was significantly associated with less PNI (univariable odds ratio [OR] 0.54, 95% confidence interval [CI] 0.37-0.79, P = 0.001; multivariable OR 0.65, 95% CI 0.43-0.99, P = 0.045). Acute prostate inflammation was associated with less PNI only in univariable analysis (univariable OR 0.51, 95% CI 0.29-0.89, P = 0.018; multivariable OR 0.63, 95% CI 0.35-1.13, P = 0.12). ConclusionAcute and chronic prostate inflammation were both associated with a lower prevalence of PNI in prostate biopsies positive for PCa. If confirmed, this suggests that inflammation and immunomodulation can serve as areas of potential therapeutic design to mitigate PNI in patients with PCa.