Prostatic calculi detected in peripheral zone of the gland during a transrectal ultrasound biopsy can be significant predictors of prostate cancer

Abstract

Purpose: Prostatic calculi (PC) are usually associated with benign prostatic hyperplasia or chronic inflammation. However, in several studies prostatic inflammation and calcification have been implicated in the pathogenesis of prostate cancer (CaP). We evaluated the prevalence of PC during transrectal ultrasound (TRUS) and correlate the ultrasonographic patterns with histological findings. Methods: A prospective study of 664 patients undergoing TRUS and prostate biopsy was planned. A standardized reproducible technique was used with using a GE Logiq 7 machine equipped with a 5-9MHz multi-frequency convex probe “end-fire”. We defined marked presence of PC as multiple hyperechoic foci with significant area (≥ 3 mm in the largest diameter). PC were classified according to zone distribution into the gland: transitional zone (TZ), central zone (CZ), and peripheral zone (PZ). Results: No significant difference was noted between the patients with PC and without PC, when comparing age, preoperative PSA level, prostate volume, and biopsy number, except for DRE findings. 168 patients (25.3%) had marked presence of PC on TRUS: 50.6% in TZ, 20.2% in CZ, and 29.2% in PZ. 31 patients (63.3%) with presence of PC in PZ had CaP on biopsy. The correlation observed between CaP and the presence of PC in PZ was statistically significant (p < 0.001). However, among patients in the CaP group there was no statistical association between PC and moderate or high Gleason grade. Conclusions: This study suggests that chronic prostatic inflammation and PC have a role in the biogenesis of cancer. CaP was more frequent in patients with PC in PZ of the gland, but was not associated with higher Gleason grade among these patients (p < 0.001).