Analysis of repeated 24-core saturation prostate biopsy: Inverse association between asymptomatic histological inflammation and prostate cancer detection.

Saturation prostate biopsy protocols have been developed to improve the prostate cancer (PCa) detection rate, particularly in the setting of repeat biopsies. The present study attempted to clarify the association between PCa detection and various risk factors in repeat saturation biopsies. A retrospective analysis was conducted on 78 Japanese patients for whom findings had caused suspicion of PCa despite previous negative prostate biopsies, and who consecutively underwent a 24-core transperineal repeat biopsy at Toyama University Hospital (Toyama, Japan). PCa was confirmed histologically in 16 of the 78 patients (20.5%). A univariate analysis revealed that the prostate-specific antigen (PSA) level at repeat biopsy was higher (P<0.01), the fPSA/tPSA ratio was lower (P=0.04), the total prostate volume was smaller (P=0.01) and the PSA density was higher (P<0.01) in PCa patients than in patients with benign prostatic disease (BPD). Histological inflammation was more frequently observed in BPD patients than in PCa patients (P<0.01). A multivariate analysis revealed that histological inflammation was the only independent predictor of the presence of a malignant lesion on repeat biopsy (odds ratio, 0.027; P=0.01). It must be considered that inflammation may cause a PSA increase in some patients with a negative initial biopsy, leading to unnecessary repeat biopsy.