The double-decking method for rezūm water vapor therapy in benign prostatic hyperplasia: volumetric, functional, and dosimetric outcomes

Abstract

Abstract Background Lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH) significantly impact quality of life in aging men. Conventional Rezūm water vapor therapy consistently achieves only a modest 25–30% prostate volume reduction, leaving a clinically meaningful therapeutic gap—particularly for larger glands where single-plane periurethral injection fails to achieve adequate thermal coverage of the entire transition zone. Objectives To evaluate the efficacy and safety of a dual-layered injection strategy (“Double-decking method”) for Rezūm water vapor therapy, targeting a treatment cycles per unit prostate volume (CPV) > 0.15, in patients with symptomatic BPH. Design Retrospective analysis of a prospectively maintained database of consecutive patients treated at a single institution. Methods We enrolled 26 consecutive patients with symptomatic BPH (April 2025–December 2025) who underwent Rezūm therapy using the “Double-decking method,” in which two sequential injections were performed within each field-of-view—one targeting the anterior and one the posterior aspect of the transition zone—targeting a CPV > 0.15. The primary endpoint was prostate volume (PV) reduction at 3 months; secondary endpoints included IPSS, Qmax, post-void residual (PVR), ejaculatory function assessed by the MSHQ-EjD, and erectile function assessed by the IIEF-5. Results The mean CPV was 0.19. Total prostate volume decreased by 50.7% ( p < 0.001). Qmax improved by + 203.5% ( p < 0.001), PVR decreased by 95.2% ( p < 0.001), and IPSS declined by 77.2% ( p < 0.001). All 7 catheter-dependent patients achieved catheter independence. MSHQ-EjD scores showed a statistically significant but clinically non-meaningful decline at 3 months (− 1.4 points; p = 0.003), below the MCID of 3 points. IIEF-5 scores showed no significant change at 3 months (− 0.1 points; p = 0.705), with no change in ED severity distribution. Grade II adverse events occurred in 4 patients (15.4%); no Grade ≥ III complications were observed. Subgroup analysis demonstrated consistent PV reduction across all volume categories (47.9–53.2%), with a significant between-group difference in Qmax ( p = 0.013). A non-significant trend toward a plateau was observed beyond CPV ≈ 0.20. Conclusion In this single-centre cohort, the Double-decking method was associated with substantial prostate volume reduction and a favorable safety profile through optimized dual-layered CPV delivery. A therapeutic window of CPV 0.15–0.20 is proposed as a hypothesis-generating observation requiring prospective validation. Trial registration Not applicable (retrospective study).