Possible clinical implications of prostate capsule thickness and glandular epithelial cell density in benign prostate hyperplasia

PURPOSE: The negative correlation between BPH-size and incidence of prostate cancer (PCa) is well-documented in the literature, however the exact mechanism is not well-understood. The present study uses histo-anatomical imaging to study prostate volume in correlation to prostate capsule thickness, and glandular epithelial cell density within the peripheral zone (PZ). MATERIALS AND METHODS: Specimens were selected from radical prostatectomies ranging from 20 to 160 mL based on ease of anatomical reconstruction by the slides. A total of 60 patients were selected and underwent quantitative measurements of prostate capsule thickness and glandular epithelial density within the PZ using computer-based imaging software. Pearson's correlation and a stepwise multiple linear regression analysis was conducted to determine the relationship between these measured parameters and the clinical characteristic of these patients. RESULTS: Pearson's correlation analysis revealed a strongly significant, negative correlation between prostate volume and glandular epithelial cell density (r(58)=−0.554, p<0.001), and a strongly significant, positive correlation between prostate volume and average capsule thickness (r(58)=0.462, p<0.001). Results of multiple regression analysis showed that average glandular epithelial cell density added statistically to this prediction (p<0.05). CONCLUSIONS: The results suggest that growth of the transition zone in BPH causes increased fibrosis of the PZ, leading to atrophy and fibrosis of glandular cells. As 80% of PCa originates from the glandular epithelium within the PZ, this observed phenomenon may explain the inverse correlation between BPH and PCa that is well-documented in the literature.