Prostatic inflammation detected in initial biopsy specimens and urinary pyuria are predictors of negative repeat prostate biopsy

Purpose: Asymptomatic prostatic inflammation may cause increased prostate specific antigen in some men, leading to unnecessary repeat prostate biopsy. We determined whether histological findings of inflammation in initial biopsy specimens and/or clinical indicators of inflammation could predict the outcome of subsequent biopsy in men with a negative initial biopsy.

Materials and methods: A total of 105 Japanese men with increased prostate specific antigen underwent repeat prostate biopsy after initial biopsy revealed no evidence of carcinoma. Of the cases 45 (42.8%) were positive for prostate cancer at repeat biopsy. We evaluated initial biopsy specimens for evidence of inflammation by mononuclear and polymorphonuclear leukocytes, serum and urinary white blood count, and C-reactive protein.

Results: Polymorphonuclear leukocyte infiltrates, urinary white blood count, patient age, prostate specific antigen at repeat biopsy, prostate volume, prostate specific antigen velocity and prostate specific antigen density were associated with the repeat biopsy outcome (p <0.05). Multivariate analysis revealed that age, prostate specific antigen density and urinary white blood count were independent predictors of outcome. On subgroup analysis of 63 men with serum prostate specific antigen less than 10 ng/ml before initial biopsy polymorphonuclear and mononuclear leukocyte inflammation, age, prostate specific antigen at repeat biopsy, prostate volume, prostate specific antigen velocity and prostate specific antigen density were associated with the outcome of repeat biopsy (p <0.05). Multivariate analysis showed that polymorphonuclear leukocyte infiltrate, prostate specific antigen density and age were independent predictors.

Conclusions: Age, prostate specific antigen density, polymorphonuclear leukocyte inflammation in initial biopsy specimens and urinary pyuria are indicators of benign repeat biopsy. They help avoid unnecessary repeat biopsy in men with increased prostate specific antigen.