Association between prostate size and glandular tissue volume of the peripheral zone via novel combined MRI and histopathology: possible pathophysiological implications on prostate cancer development.

PURPOSE

Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are the two most prevalent urologic diseases affecting elderly men. An inverse relationship between BPH/prostate size and PCa incidence is well documented in the current literature, but the precise mechanism is poorly understood. This study aims to investigate the effect of total prostate volume on total glandular tissue volume of the peripheral zone via a novel combination of magnetic resonance imaging (MRI) and histo-anatomical imaging.

METHODS

42 male patients between ages 53-79 years underwent both radical prostatectomy and pre-operative MRI scans. Prostate sizes ranged from 14.8-133.3cc. Quantitative measurements of surgical capsule thickness and glandular epithelial cell density within the peripheral zone (PZ) were obtained on histo-anatomical slides using computer-based imaging software. Quantitative prostatic zonal measurements were obtained from MRI scans. Combining MRI- and histopathology-obtained parameters allowed measurement of the total glandular tissue volume of the PZ (GVPZ). Statistical analysis was performed to identify associations between total prostate volume (TPV) and GVPZ.

RESULTS

The Mann-Whitney U-test showed significant decreases in GVPZ in larger prostates when compared to smaller prostates.

CONCLUSIONS

Combined MRI and histopathology techniques provide a novel method for accurate measuring of glandular tissue content within the prostatic PZ. The findings of this pilot study support the hypothesis of PZ compression by an expanding transition zone in large BPH prostates, leading to atrophy of PZ glandular tissue. As the majority of PCa originates in the PZ, this dynamic process may explain the protective effect of large BPH prostates against PCa development.