AQUABEAM® Robotic System and Ultrasound Accessories (AQUA Study)

A- Background:

Lower urinary symptoms (LUTS) affect many older men and their frequency and severity increase with age. In the age group between 65 and 79 years the rate of men with moderate and severe LUTS is 20 - 25%. This rate increases to 90% in men over 80 years old. The complaints are potentially associated with a considerable impairment of the quality of life. LUTS in older men are commonly caused by a bladder outlet obstruction (BOO) secondary to benign prostatic enlargement (BPE). The histological term "benign prostatic hyperplasia" (BPH) is frequently used in literature and clinical practice as a synonym for this diagnosis.

Surgical therapy of BPH has continuously evolved in recent years. Transurethral resection of the prostate (TUR-P) is the current gold standard for the endoscopic management of small to medium prostate volumes. The development of laser-assisted transurethral and other innovative techniques (e.g. REZUM, UROLIFT) have supplemented the surgical spectrum. For large prostate volumes above 80 mL, transurethral laser enucleation (holmium, thulium) is widely established in clinics as an alternative to conventional open surgical simple prostatectomy.

One of the latest technologies for transurethral prostate desobstruction is the Aquablation therapy, first described in 2015 (AQUABEAM®, PROCEPT BioRobotics, Redwood Shores, CA, USA). The device applies an ultrasound-guided water jet that precisely ablates the prostate tissue. The second generation of this robot-assisted system is CE-certified and gained market access in Australia, New Zealand, Canada, and the United States. This device for this study is the third generation of the AQUABEAM Robotic System, which is currently only commercialized in the US.

In recent years, the technology has been evaluated in a total of three monocentric and three multicentric prospective studies. So far, one randomized controlled trial (RCT) has been conducted - the WATER study. The multi-center study, designed as a double-blind, randomized controlled trial, compares the Aquablation therapy with the gold standard TUR-P in small and medium prostate sizes (30-80 mL). The primary endpoint was defined as IPSS change 6 months postoperatively. The primary safety endpoint was stated as the rate of adverse events three months after surgery with a Clavien-Dindo grade ≥ 2 or a Clavien-Dindo grade 1 with persistent dysfunctions such as incontinence, erectile dysfunction or ejaculation disorders. The WATER study confirmed the non-inferiority of the Aquablation therapy regarding the two primary endpoints. The results for the secondary endpoints erectile function (IIEF) and ejaculatory function (MSHQ-EjD) were significantly better in the Aquablation-arm. Interestingly, a subgroup analysis of the WATER patient collective revealed significantly better results regarding IPSS reduction, the primary safety endpoint and the rate of postoperative anejaculation for patients with medium prostate volumes (50-80 mL).