Impact of Median Lobe Protrusion on Outcomes of Water Vapor Thermal Therapy for Benign Prostatic Hyperplasia: A Prospective Analysis

Abstract

Purpose:

To evaluate outcomes after water vapor thermal therapy (WVTT) for benign prostatic hyperplasia (BPH), stratified by varying degrees of median lobe (ML) protrusion.

Patients and Methods:

We enrolled men aged ≥45 years with BPH who underwent WVTT from July 2020 to September 2023. Inclusion criteria were an estimated prostate volume of 30–80 cc, International Prostate Symptom Score (IPSS) ≥12, and maximum urinary flow rate <16 mL/sec. ML protrusion was assessed using ultrasound (with bladder volume ≥250 cc) and flexible cystoscopy; the average of both measurements was used to classify ML protrusion into <5 mm, 5–10 mm, and >10 mm. Primary outcomes included postoperative complications such as surgical retreatment, acute urinary retention (AUR), and urinary tract infections (UTIs).

Results:

With a median follow-up of 29.1 months (range: 24–36), improvements in lower urinary tract symptoms (LUTS) were similar across all groups, with consistent symptom reduction (Δ = −13) in both obstructive and irritative IPSS components. Rates of AUR and UTIs showed no significant variation across groups: AUR (no ML 9.5%; <5 mm 8.7%; 5–10 mm 12%; >10 mm 17%; p = 0.7) and UTI (no ML 8.4%; <5 mm 4.3%; 5–10 mm 9.3%; >10 mm 8.3%; p = 0.8). Despite comparable preoperative characteristics, surgical retreatment rates varied significantly with ML protrusion: no ML (3.2%), <5 mm (4.3%), 5–10 mm (14%), and >10 mm (21%) (p = 0.007), highlighting increased retreatment risk associated with greater ML protrusion.

Conclusions:

WVTT effectively relieves LUTS across all ML configurations. However, patients with greater ML protrusion may face a higher risk of retreatment, likely because of increased bladder neck and urethral involvement. These findings suggest that detailed ML assessment can aid in patient counseling and stratification.