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.

Robotic-assisted laparoscopic pyelolithotomy with intracorporeal pyeloscopy in a horseshoe kidney.

Horseshoe kidneys are one of the most common congenital genitourinary malformations and can increase the complexity of common urologic procedures, especially nephrolithiasis. We present a patient who underwent robotic-assisted laparoscopic pyelolithotomy with intracorporeal pyeloscopy and stone basketing to treat a left lower pole stone burden located in a horseshoe kidney. This procedure provided benefits of expanded maneuverability, dexterity, and stability, which resulted in successful elimination of stone burden on post-operative imaging. We believe that robotic-assisted laparoscopic pyelolithotomy with intracorporeal pyeloscopy should be considered as a treatment option in similar cases of complicated nephrolithiasis due to complex renal anatomy.

Association Between Prostate Size and MRI Determined Quantitative Prostate Zonal Measurements.

Purpose: Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are the two most prevalent and common urologic diseases impacting elderly men. The current literature has well documented an inverse relationship between prostate/BPH-size and incidence of PCa, but the exact interaction between these two disease entities is not well understood. The purpose of this study is to analyze prostatic zonal measurements with magnetic resonance imaging (MRI) in order to investigate the dynamic changes of the transition zone (TZ) and peripheral zone (PZ) in response to prostate/BPH growth. Methods: Multiparametric magnetic resonance imaging (mpMRI) scans of 430 consecutive male patients aged 18-89 years were obtained to measure the different zonal areas of the prostate. The data were statistically analyzed to identify specific associations between the different measurement parameters and total prostate volume (TPV). Results: The Mann-Whitney U-test showed a significant decline of the average peripheral zone thickness (PZT) (z = -4.5665, p < 0.0001) in larger prostates when compared to smaller prostates. The Spearman correlation between TPV and PZT demonstrated a significant negative correlation (-0.20, p < 0.0001). Conclusion: The data revealed that PZT was significantly smaller in the subgroup of patients with higher TPV. This supports the hypothesis of PZ compression and thinning caused by the growing and expanding TZ in BPH prostates. This dynamic growth-related process in the different prostatic zones may explain the protective effect of BPH against PCa.

Quantitative measurements of prostatic zones by MRI and their dependence on prostate size: possible clinical implications in prostate cancer.

AIM: Many studies support an inverse relationship between benign prostate hypertrophy (BPH) size and incidence of prostate cancer (PCa), but the causal link between these conditions is poorly understood. Recent studies suggest that a growing transition zone (TZ) in the prostate may induce pressure on the outer peripheral zone (PZ), leading to atrophy of the glandular tissue where PCa often originates, providing a possible explanation for this interaction. To further investigate this phenomenon, our pilot study uses magnetic resonance imaging (MRI) to examine quantitative zonal changes in a consecutive cohort of prostates. METHODS: MRI scans of male patients [n = 204, 61.57 ± 13.90 years, average body mass index (BMI) 29.05 kg/m2] with various prostate sizes were analyzed statistically to identify possible associations between prostate parameters, such as total prostate volume (TPV) and peripheral zone thickness (PZT). RESULTS: TPV and PZT demonstrated a weak, inverse correlation (r = -0.21, p = 0.002). However, when examining the plotted data, the relationship between TPV and PZT was significantly different when the cohort was divided into two groups; lower TPV: ⩽87.5 ml (n = 188, TPV x- = 36.01 ± 18.18 ml), and higher TPV: >87.5 ml (n = 17, TPV x- = 125.69 ± 41.13 ml). Average PZT differed significantly between these groups (z = -3.5554, p = 0.0004). CONCLUSIONS: PZT was significantly different for patients with lower versus higher TPVs, suggesting that, above a certain point of BPH growth, the PZ is unable to withstand pressure from an expanding TZ, supporting the notion that growing BPH causes compression of the PZ glandular tissue, and, therefore, BPH may be protective against PCa.