# One-Year Clinical Outcomes of Water Vapor Thermal Therapy for Benign Prostatic Hyperplasia: A Single-Center Experience of 52 Patients

## TL;DR

This study reports on the one-year outcomes of water vapor thermal therapy for benign prostatic hyperplasia in Japan, showing it is safe and effective with sustained improvements.

## Contribution

This is the first Japanese single-center report on one-year clinical outcomes of outpatient water vapor thermal therapy for BPH.

## Key findings

- Significant improvements in quality of life, prostate volume, and postvoid residual volume were maintained for 12 months.
- All procedures were completed as day-case interventions with minimal adverse events.
- Larger prostate volume was identified as a risk factor for medication restart and first trial of void failure.

## Abstract

Introduction

Water vapor thermal therapy (WVTT) has emerged as a minimally invasive surgical therapy (MIST) for benign prostatic hyperplasia (BPH) management. While international studies have confirmed its safety and efficacy, real-world data from Japanese outpatient clinics remain scarce. This study aimed to evaluate the one-year clinical outcomes of WVTT performed in a single urology clinic, representing the first Japanese single-center report describing one-year clinical outcomes of outpatient WVTT.

Methods

We conducted a retrospective cohort study at Mizuhodai Urology, including 52 patients who underwent WVTT between March 2023 and September 2024. Baseline and follow-up assessments at one, three, six, and 12 months included quality of life (QOL, International Prostate Symptom Score (IPSS)-QOL), prostate volume (PV), and postvoid residual (PVR) volume. Adverse events (AEs) were classified using the Clavien-Dindo system. Risk factors for the restart of BPH medication and failure of the first trial of void (TOV) were analyzed using multivariate logistic regression.

Results

Significant improvements in QOL, PV, and PVR were maintained throughout the 12-month follow-up period. All procedures were completed as day-case interventions under spinal anesthesia, with a median operative time of 3 min and a mean hospitalization duration of 259 min. Catheter removal was achieved in all patients, although the first TOV failed in seven cases. Restart of BPH medication was required in seven patients after a median of 339 days. Multivariate analysis identified PV ≥60 mL as a risk factor for medication restart and PV ≥70 mL for first TOV failure. AEs occurred in six patients within 14 days, all grade I-II, with no grade ≥III events.

Conclusion

Clinic-based WVTT was safe and effective for BPH management, with sustained improvement in QOL, PV, and PVR at one year. To the best of our knowledge, this is the first Japanese study reporting one-year outcomes of WVTT. These results support its feasibility as a minimally invasive, office-based therapy while underscoring the importance of patient selection in larger prostates.