Relationship between Chronic Inflammation at Prostate Biopsy and Transition Zone Prostate Volume Enlargement in a Prospectively UK Screened Population

Abstract

Objective:

The aim of this study was to evaluate the relationship between histological prostatic inflammation and prostate volume at the time of prostate biopsy.

Patients and methods:

From a prospective prostate cancer screening study, 137 men aged 50–65 years, underwent prostate biopsies negative for cancer, forming the study population. Biopsy criteria were prostate specific antigen (PSA) >4 ng/ml (n = 40), or between 1.1 and 4ng/ml with a percent free PSA (%fPSA) <25% (n = 97). Total gland (TG) and transition zone (TZ) volumes were measured prior to TRUS guided biopsy. Histological classification included chronic inflammation (CIlymphocyte predominant), active inflammation (AI-neutrophil predominant), and benign prostatic tissue (BPT-no inflammatory cells). A logistic regression analysis was performed using age, TPSA, %fPSA, histology, TZ and TG volume, TZ/TG ratio, PSA density, and transition zone PSA density as continuous variables. We also mailed validated self-administered symptom scores to men in the three histological subgroups (men without cancer) at a median of follow up of 6.5 years (range 5.9–7.1 years) after screening and biopsy.

Results:

Histological chronic inflammation (n = 78, 57%) at biopsy was associated with a larger mean TG volume (30.8cc) than active inflammation (n =7, 22.7cc) and benign prostatic tissue (n = 52, 25.9cc). On bivariate analysis, chronic inflammation was associated with greater TZ volume (p = 0.0015) and TZ/TG ratio (p = 0.0008). On multivariate analysis, chronic inflammation was the only independent variable associated with a greater ratio of the TZ to TG volume (odds ratio 478, p = 0.005). IPPS symptoms scores were completed and returned by 88 men (66% compliance). In men with chronic inflammation (49), active inflammation (5), and benign tissue (30), the mean IPSS scores were 10.9, 7.2, and 8.7, respectively. These differences did not reach statistical significance p > 0.05.

Conclusions:

In this younger screened population, chronic inflammation was associated with greater prostate gland volume secondary to transition zone volume enlargement. Further research is needed to establish a causally related link for this observation.