INTRODUCTION AND OBJECTIVES: Relief of lower urinary tract symptoms (LUTS), those due to benign prostatic hyperplasia (BPH), is only relevant if commensurate with improving patients' perception of improved quality of life (QOL). We evaluated 4 year outcome data from the randomized double-blind, controlled trial (RCT) of water vapor thermal therapy for treatment of moderate-to-severe LUTS/BPH, and also determined the minimal important differences (MIDs) in International Prostate Symptom Scores (IPSS) associated with meaningful changes in QOL. METHODS: Total 188 subjects; 135 men ≥50 years old with IPSS ≥13, maximum flow rate (Qmax) ≤15 ml/s and prostate volume 30-80 cm3 treated once in the RCT for Rezum® System thermal therapy were followed for 4 years and a subset of 53 men who requalified for cross-over from control (sham rigid cystoscopy) to active treatment were followed for 3 years. IPSS-QOL was used in a method for anchor-based analysis to determine MID in IPSS point changes related to degrees of improved QOL for each severity category of LUTS. RESULTS: Mean symptom relief was significantly improved within 3 months or less (IPSS 50%, QOL 46%, Qmax 69%, BPH Impact Index 46%) after thermal therapy and remained consistently durable (IPSS 46%, QOL 42%, Qmax 50%, BPH Impact Index 51%) throughout 4 years (p<0.0001); outcomes were similarly sustained in crossover subjects at 3 years. Targeted ablation was to all prostate zones including an obstructing median lobe and/or enlarged central zone. No late related adverse events occurred and no de novo erectile dysfunction was reported. IPSS and QOL scores are very strongly correlated (Spearman correlation coefficient = 0.67 - 0.72) after water vapor thermal therapy. The estimated mean change in IPSS score from baseline corresponding to a one point QOL change for each LUTS severity level is approximately -5 points for mild (IPSS 13-19), -8.2 for moderate (IPSS 20-26) and -11.7 for severe LUTS (IPSS 27-35), p<0.0001. The MID was quite consistent across time points over 3 years. In general, men had a mean ∼50% improvement in QOL (from "mostly dissatisfied" to "mostly satisfied" with urinary condition; score decrease from 4 to 2). CONCLUSIONS: The MID offers a threshold above which the outcome is experienced as providing a noticeable improvement in QOL by the patient. Water vapor thermal therapy provided effective symptom relief and improved QOL that remains durable for over 4 years. This minimally invasive therapy is applicable to all prostate zones with procedures performed under local anesthesia in an office setting. SOURCE OF FUNDING: Boston Scientific.
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