Evolving Hypothesis that Prostate/BPH Size Matters in Protection against Prostate Cancer

Abstract

Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are the two predominant urologic diseases affecting aging men. As a matter of fact, 95–98% of elderly men with prostate as their “primary organ disease” for consulting urologists have either the clinical diagnosis of BPH, PCa or both. Other primary diagnoses of the prostate such as sarcoma, lymphoma or isolated bacterial prostatitis (not in the context of a systemic urinary tract infection) are rare entities. Although BPH and PCa are very common, their interaction is currently not well understood. Numerous clinical studies and meta-analysis reviews have demonstrated a negative correlation between prostate BPH size and the probability of PCa presence, but little is known to explain this clinical phenomenon. Recent histo-anatomical and magnetic resonance imaging studies have revealed data leading to a hypothesis indicating the expanding transition zone (TZ) in a growing BPH prostate causes mechanical stress within the peripheral zone (PZ) with secondary fibrosis and atrophy of the glands within the PZ. This dynamic interaction of the TZ against the PZ in a growing BPH-prostate could explain the negative correlation between BPH size and PCa incidence. The purpose of this review is to present and discuss the evolving hypothesis that prostate size may matter and be protective against prostate cancer.