WATER versus WATER II 2-Year Update: Comparing Aquablation Therapy for Benign Prostatic Hyperplasia in 30-80-cm3 and 80-150-cm3 Prostates

David-Dan Nguyen; Neil Barber; Mo Bidair; Peter Gilling; Paul Anderson; Kevin C Zorn; Gopal Badlani; Mitch Humphreys; Steven Kaplan; Ronald Kaufman; Alan So; Ryan Paterson; Larry Goldenberg; Dean Elterman; Mihir Desai; Jim Lingeman; Claus Roehrborn; Naeem Bhojani

doi:10.1016/j.euros.2021.01.004

WATER versus WATER II 2-Year Update: Comparing Aquablation Therapy for Benign Prostatic Hyperplasia in 30-80-cm³ and 80-150-cm³ Prostates

Eur Urol Open Sci. 2021 Jan 31:25:21-28. doi: 10.1016/j.euros.2021.01.004. eCollection 2021 Mar.

Authors

David-Dan Nguyen¹, Neil Barber², Mo Bidair³, Peter Gilling⁴, Paul Anderson⁵, Kevin C Zorn⁶, Gopal Badlani⁷, Mitch Humphreys⁸, Steven Kaplan⁹, Ronald Kaufman¹⁰, Alan So¹¹, Ryan Paterson¹¹, Larry Goldenberg¹¹, Dean Elterman¹², Mihir Desai¹³, Jim Lingeman¹⁴, Claus Roehrborn¹⁵, Naeem Bhojani⁶

Affiliations

¹ Faculty of Medicine, McGill University, Montreal, Canada.
² Department of Urology, Frimley Park Hospital, Frimley, UK.
³ San Diego Clinical Trials, San Diego, CA, USA.
⁴ Department of Urology, Bay of Plenty District Health Board Clinical School, Tauranga, New Zealand.
⁵ Department of Urology, Royal Melbourne Hospital, Melbourne, Australia.
⁶ Division of Urology, Centre Hospitalier de l'Université de Montréal, Montreal, Canada.
⁷ Department of Urology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
⁸ Department of Urology, Mayo Clinic, Phoenix, AZ, USA.
⁹ Department of Urology, Mount Sinai Hospital, New York, NY, USA.
¹⁰ Division of Urology, Albany Medical College, Albany, NY, USA.
¹¹ Urologic Sciences, University of British Columbia, Vancouver, Canada.
¹² Division of Urology, University of Toronto, Toronto, Canada.
¹³ USC Institute of Urology, University of Southern California, Los Angeles, CA, USA.
¹⁴ Institute for Kidney Stone Disease, Methodist Hospital, Indianapolis, IN, USA.
¹⁵ Department of Urology, UT Southwestern Medical Centre, Dallas, TX, USA.

Abstract

Background: Surgical options are limited when treating large (>80 cm³) 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-cm³ prostates with the outcome for 80-150-cm³ 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 cm³. WATER II is a prospective, multicenter, single-arm international clinical trial of Aquablation in men with a prostate of 80-150 cm³.

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 cm³/s in WATER and WATER II, improving to 20.5 and 18.2 cm³/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 cm³ and patients with a prostate of 80-150 cm³ 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.

Keywords: Aquablation; Benign prostatic hyperplasia; Robotics.