Water Vapor Therapy for the Management of Prostate Cancer: The VAPOR 2 Study Initial Results of Ablative Efficacy and Toxicity.

Abstract

The safety and effectiveness of water vapor for ablation of prostate tissue was assessed in men with intermediate-risk localized prostate cancer (PCa). A prospective, multicenter, single arm study (VAPOR 2) was conducted in 235 men at 26 centers across the United States in men ≥ 50 years, with Gleason Grade Group 2 (GG2) PCa confined to a single PI-RADS 3 or 4 abnormality on multiparametric magnetic resonance imaging (mpMRI) fusion biopsy, prostate-specific antigen (PSA) level ≤ 15 ng/ml, and clinical stage ≤ T2c. Data presented is a predefined subset analysis of 110 men completing 12-month follow-up to assess only ablative efficacy and toxicity. Reported outcomes include biopsy 6 months post-treatment, PSA, prostate volume reduction, urinary/sexual function, quality-of-life questionnaires, and adverse events. The 3-year follow-up analysis will evaluate efficacy in PCa management, with 5 years of total follow-up. The median age was 65 years, with a median baseline PSA of 5.6 ng/mL and prostate volume of 40.7 cc. On 6-month biopsy, targeted sampling of the treated region revealed benign tissue only in 75% and benign tissue or GG1 PCa in 91%. Regression analysis did not identify a significant baseline predictor of positive biopsy. PSA showed a median reduction of 58%, with a median 8cc reduction in prostate volume. Urinary and sexual function showed an initial decline followed by gradual recovery through 12 months. Perioperative adverse events were generally mild and resolved without sequelae, with no reports of rectal injury. The VAPOR 2 study demonstrated effective ablation of prostate tissue in men with localized, intermediate risk PCa with low rates of procedural morbidity.