Clinical significance of peripheral zone thickness in men with lower urinary tract symptoms/benign prostatic hyperplasia

Objective To evaluate the clinical impact of prostate peripheral zone thickness (PZT), based on presumed circle area ratio (PCAR) theory, on urinary symptoms in men with lower urinary tract symptoms/benign prostatic hyperplasia (LUTS/BPH) as a novel prostate parameter. Patients and methods Medical records were obtained from a prospective database of first-visit men with LUTS/BPH. Age, international prostate symptom score (IPSS), overactive bladder symptom score (OABSS), maximum urinary flow rate (Q_max), and post-void residual urine volume (PVR) were assessed. Total prostate volume (TPV), transition zone volume (TZV), transition zone index (TZI), and PZT were measured by transrectal ultrasonography. Reliability analysis was also performed. Results In all, 1009 patients were enrolled for the analysis. The mean (sd) PZT was 11.10 (2.50) mm, and patients were classified into three groups PZT thickness groups; PZT <9.5 mm, ≥9.5 to <13 mm, and ≥13 mm. As the PZT became smaller, all urinary symptom scores including IPSS, quality of life (QoL), and OABSS significantly increased. Uroflowmetry variables, such as Q_max and PVR, also showed significant differences. PZT showed a high intra-class correlation coefficient (0.896). Multivariate analysis revealed that the PZT was independently associated with IPSS (P < 0.001), QoL (P = 0.003), OABSS (P = 0.001), and PVR (P = 0.001), but PZT influence on Q_max was only of borderline significance (P = 0.055). Conclusion PZT is a novel, easy-to-measure prostate parameter that is significantly associated with urinary symptoms. Our present findings suggest that clinical usefulness of PZT should be further validated for managing men with LUTS/BPH.