WATER versus WATER II 2-Year Update: Comparing Aquablation Therapy for Benign Prostatic Hyperplasia in 30–80-cm(3) and 80–150-cm(3) Prostates

BACKGROUND: Surgical options are limited when treating large (>80 cm(3)) prostates for lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Open simple prostatectomy remains the most common procedure performed for large prostates. There is a need for novel surgical approaches with shorter learning curves and effective treatment. Aquablation could be this novel tool. OBJECTIVE: To compare the outcome of Aquablation for 30–80-cm(3) prostates with the outcome for 80–150-cm(3) prostates at 2-yr follow-up. DESIGN, SETTING, AND PARTICIPANTS: We used data from two trials. WATER is a prospective, double-blind, multicenter, international clinical trial comparing the safety and efficacy of Aquablation and transurethral resection of the prostate in the treatment of LUTS/BPH in men aged 45–80 yr with a prostate of 30–80 cm(3). WATER II is a prospective, multicenter, single-arm international clinical trial of Aquablation in men with a prostate of 80–150 cm(3). INTERVENTION: Aquablation, an ultrasound-guided, robotically executed waterjet ablative procedure. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We compared 24-mo outcomes between 116 WATER and 101 WATER II study subjects. Student’s t test or a Wilcoxon test was used to compare continuous variables and Fisher’s test for categorical variables. RESULTS AND LIMITATIONS: The International Prostate Symptom Score (IPSS) reductions at 24 mo was 14.5 points for WATER and 17.4 points for WATER II (p = 0.31). At baseline, the maximum urinary flow rate (Q(max)) was 9.4 and 8.7 cm(3)/s in WATER and WATER II, improving to 20.5 and 18.2 cm(3)/s, respectively (p = 0.60) at 24 mo. Improvements in both IPSS and Q(max) were immediate and sustained throughout follow-up. At 2 yr, the surgical retreatment rate was 4% in WATER and 2% in WATER II. CONCLUSIONS: Aquablation is effective in patients with a prostate of 30–80 cm(3) and patients with a prostate of 80–150 cm(3) treated for LUTS/BPH, with comparable outcomes in both groups. It has low complication and retreatment rates at 2 yr of follow-up, with durable improvements in functional outcome. PATIENT SUMMARY: Outcomes of Aquablation for both small-to-moderately-sized and large prostates are similar and sustainable at 2 yr of follow-up.