Geographic differences in baseline prostate inflammation and relationship with subsequent prostate cancer risk: results from the multinational REDUCE trial

Prostate cancer (PC) incidence rates vary 25-fold worldwide. Differences in PSA screening are largely, but not entirely, responsible. We examined geographic differences in prevalence of histologic prostate inflammation and subsequent PC risk.

7,000 non-Hispanic white men were enrolled in the REDUCE trial from Europe (n=4,644), North America (n=1,746), South America (n=466), and Australia/New Zealand (n=144). Histologic inflammation in baseline negative prostate biopsies was classified as chronic (lymphocytes/macrophages) or acute (neutrophils). Multivariable logistic regression was used to examine associations between region and prostate inflammation, and between region and PC risk at 2-year biopsy.

Prevalence of prostate inflammation varied across region, with broadly similar patterns for acute and chronic inflammation. Relative to Europe, prevalence of acute inflammation was higher in North America (OR 1.77; 95%CI 1.51-2.08) and Australia/New Zealand (OR 2.07; 95%CI 1.40-3.06). Men from these regions had lower PC risk than Europeans at biopsy. Among North Americans, prevalence of acute inflammation was higher in Canada versus the US (OR 1.40; 95%CI 1.07-1.83), but PC risk did not differ between these regions. Among Europeans, prevalence of acute inflammation was lower in Northern and Eastern (OR 0.79; 95%CI 0.65-0.97 and OR 0.62; 95%CI 0.45-0.87, respectively), relative to Western Europe, and these men had higher PC risk at biopsy.

Prevalence of histologic prostate inflammation varied by region. Geographic differences in prostate inflammation tracked inversely with geographic differences in PC risk.

Characterization of premalignant prostate biology and the relationship with subsequent prostate cancer risk could inform prostate cancer prevention efforts.

Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology. 2018 Apr 18 [Epub ahead of print]

Emma H Allott, Sarah C Markt, Lauren E Howard, Adriana C Vidal, Daniel M Moreira, Ramiro Castro-Santamaria, Gerald L Adriole, Lorelei A Mucci, Stephen J Freedland

Department of Nutrition, University of North Carolina at Chapel Hill ., Department of Epidemiology, Harvard T.H. Chan School of Public Health., Department of Biostatistics and Bioinformatics, Duke University School of Medicine., Surgery, Cedars-Sinai Medical Center., University of Illinois at Chicago., Metabolic Pathways and Cardiovascular R&D unit, GlaxoSmithKline Inc., Urology, Washington University School of Medicine in St. Louis.

Go Beyond the Abstract and Read a Commentary by Emma H Allott, PhD