Advice

Clinical and technical evidence

Clinical and technical evidence

A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.

Published evidence

Five studies are summarised in this briefing.

One multicentre randomised controlled trial of 181 people (Gilling et al. 2022) is included which compares outcomes for people with benign prostatic hyperplasia (BPH) who had either Aquablation therapy or transurethral resection of the prostate (TURP). There are also 2 single-centre single-arm prospective studies (Whiting et al. 2021 and Desai et al. 2018) which assess the use of Aquablation therapy in people with BPH. A single-arm study carried out at multiple centres across 5 countries is included (Bach et al. 2020). The other study is also a multicentre single-arm study (Zorn et al. 2021), which focuses on a specific patient subgroup, that is people with large prostates.

Three other studies related to the technology were also identified, but not summarised in this briefing. One study (Gloger et al. 2021) compares the haemostasis of Aquablation therapy with holmium laser enucleation of the prostate. One is a retrospective study (Elterman et al. 2021a) including 2,089 people who underwent Aquablation therapy across 11 countries in Asia, Europe and North America. This study aimed to show how the introduction of focal bladder neck cautery is associated with lower rates of post-procedure bleeding. The other is a meta-analysis (Elterman et al. 2021b) of 425 people who had Aquablation therapy for lower urinary tract symptoms (LUTS) caused by BPH in various prostate anatomies. This meta-analysis includes some of the studies summarised in this briefing.

The clinical evidence and its strengths and limitations are summarised in the overall assessment of the evidence.

Overall assessment of the evidence

The evidence base for Aquablation therapy consists of a randomised controlled trial comparing the technology directly with TURP, and several smaller studies including a single-arm study of people who had Aquablation therapy. The outcomes reported include prostate-health-related outcomes after the procedure, such as urinary flow rates and the International Prostate Symptom Score (IPSS), as well as time taken to complete the procedure, rate of complications which require retreatment, and preservation of sexual function. More evidence is needed to support some of the claimed benefits of the technology, such as reduced theatre time, reduced length of hospital stay, ability to provide day-case procedures, reduced retreatment rates and reduced adverse events. The studies have been done in a wide range of locations, including in the UK. Although the evidence base includes a randomised controlled trial comparing Aquablation therapy against standard care, including TURP, there is a need for further comparative studies comparing Aquablation therapy with other technologies used in current practice, such as holmium laser enucleation of the prostate. Relative to similar technologies for this indication, the total number of studies is small. But there are a number of ongoing studies which may address gaps in the current evidence base.

Gilling et al. (2022)

Study size, design and location

A double-blinded multicentre prospective randomised controlled trial of 181 people with BPH-related LUTS. The study was done in the US, Australia, New Zealand and the UK.

Intervention and comparator

Aquablation therapy, compared with TURP.

Key outcomes

Procedure times, defined as first instrument introduction to insertion of catheter, were similar at 40 minutes for Aquablation and 36 minutes for TURP. Mean resection time was found to be significantly lower in the Aquablation group at 4 minutes compared with 27 minutes for TURP (p<0.0001). One Aquablation patient required a blood transfusion, but no TURP patient did. Mean length of hospital stay was 1.4 days in both groups and the urinary catheter was removed at a median of 1 day after surgery in both groups. Procedure-related anejaculation was less common after Aquablation (7%) than TURP (25%), p=0.0004.

BPH symptoms were measured using the IPSS. Score improvements were similar across both groups at 12 months, with a reduction of 15.1 points after Aquablation or TURP. Mean maximum urinary flow rates increased significantly (p=0.863) in both groups. At 1 year, prostate-specific antigen was reduced significantly in both groups by 1 point (p<0.01). Rates of surgical retreatment for BPH within 1 year from the study procedure were 1.5% for TURP and 2.6% for Aquablation therapy, though this difference was not found to be significant.

At 5‑year follow up, mean IPSS reduction was 15.1 in the Aquablation group and 13.2 in the TURP group (p=0.2764). For people with prostates larger than 50 ml, IPSS reduction was 3.5 points greater in the Aquablation group compared with the TURP group (p=0.0123). Peak urinary flow rates showed a mean improvement of 8.7 ml/s or 125% improvement for the Aquablation group, compared with 6.3 ml/s or 89% improvement for TURP. After 5 years, 6% of Aquablation patients needed an additional BPH therapy as a result of recurrent LUTS, whereas 12.3% of people in the TURP arm required additional BPH therapy.

Strengths and limitations

There were many strengths of this study design: people were randomised to either study treatment, people were recruited from multiple centres in different geographical locations, and blinding was preserved until 3 years of follow up. A limitation of the study was that there was a large drop-out after 3‑year follow up, which the authors attributed to the impact of the COVID‑19 global pandemic. The study authors did not specify the method used or the name of the technology for TURP. The study was also funded by the manufacturer.

Zorn et al. (2021)

Study size, design and location

A multicentre prospective study of 101 people with BPH symptoms and large prostates (80 to 150 cm3). The study was done in the US and Canada.

Intervention and comparator

Aquablation therapy, no comparator.

Key outcomes

Maximum urinary flow rate increased from 8.7 cc/s to 18.5 cc/s. Post-void residual urinary volume decreased from 131 cm3 to 51 cm3 at 3 years. Mean serum prostate-specific antigen also decreased from 7.1 at baseline to 5.0 at 3 years. At 3-year follow up, 6% of treated patients needed BPH medication and an additional 3% required surgical retreatment for LUTS. Subgroup analysis was done for people with moderate symptoms compared to people with severe symptoms. No significant difference was found in any efficacy measure between the subgroups.

Strengths and limitations

This was a prospective study carried out across multiple centres, with scheduled pre-operative and post-operative visits and assessments. Strengths of the study were that it focused on people with large prostates and included follow up for 3 years. A limitation of the study was the lack of a control group, which prevented direct comparison with other treatment approaches. In addition, the study authors did not present results relating to the procedure itself, such as time taken for resection and average time for the entire procedure.

Bach et al. (2020)

Study size, design and location

A multicentre prospective single-arm trial of 178 people with BPH-related LUTS. The study was done in Germany, New Zealand, Lebanon, Australia and the UK.

Intervention and comparator

Aquablation therapy, no comparator.

Key outcomes

Mean duration of the procedure was 24 minutes, while the total duration of anaesthesia was 50 minutes. Operative time and anaesthesia duration increased by 0.13 minutes per cubic centimetre of prostate tissue and 0.2 minutes per cubic centimetre of prostate tissue, respectively. Median catheterisation time after surgery was 1.9 days and average length of hospital stay was 2.2 days. Five patients (2.7%) underwent blood transfusion in the first week after the procedure and 14 patients (7.9%) were taken back to the operating room for post-procedure bleeding, after which haemostasis was achieved with cautery.

Mean IPSS significantly improved from 21.7 at baseline to 7.1 at 3-month follow up and 6.4 at 12-month follow up (p<0.0001). Mean quality-of-life scores improved from 4.7 at baseline to 1.5 at 3-month follow up and 1.4 at 12-month follow up (p<0.0001). Follow-up IPSS scores were found to be independent of baseline IPSS. Maximum urinary flow rate increased from 9.9 cc/s to 20.3 cc/s at month 3 and 20.8 cc/s at month 12. Post-void residual also improved from 108 to 47 at 3 months.

Strengths and limitations

Advantages of the study include its prospective multicentre design and recruitment of patients in a non-clinical trial setting. The study involved surgeons with both high and low levels of experience with the Aquablation procedure, and similar levels of symptom relief were seen independent of surgical experience. The lack of a control group and relatively short-term efficacy follow up can be classed as limitations. The study was funded by the manufacturer.

Whiting et al. (2021)

Study size, design and location

Single centre study of 55 people with BPH having Aquablation therapy, with 12-month follow-up. The study was done in the UK.

Intervention and comparator

Aquablation therapy, no comparator.

Key outcomes

Mean time taken for the procedure was 26.9 minutes. Tissue resection time was not reported. A significant reduction was seen in mean prostate volume from 58.2 cm3 to 33.2 cm3 (p<0.0001). At 12-month follow up, maximum urinary flow rate showed significant improvements from 9.9 ml/s to 23.9 ml/s. Mean IPSS decreased from 21.7 to 6.1 and mean IPSS quality-of-life score also decreased from 4.8 to 1.4; both results were significant (p<0.0001). There was no significant change in scores for erectile function and ejaculatory dysfunction. Clavien grade 2 complications occurred in 14.5% of people.

Strengths and limitations

A significant strength of the study was that it was done in the UK with 1‑year follow up. Limitations include the lack of a comparator and the relatively small study population.

Desai et al. (2018)

Study size, design and location

Single centre study of 47 people with BPH having Aquablation therapy, with 3-month follow up. The study was done in India.

Intervention and comparator

Aquablation therapy, no comparator.

Key outcomes

Mean time taken for the procedure was 35 minutes, and tissue resection time was 4 minutes. The mean hospital stay was 3.1 days, and mean duration for urethral catheterisation was 1.9 days. At 3-month follow up, the mean IPSS decreased from 24.4 at baseline to 5.0. Mean IPSS quality-of-life score also decreased from 4.5 to 0.3. Peak urinary flow rate increased from 7.1 ml/s to 16.5 ml/s, and post-void residual urine volume decreased from 119 ml to 43 ml. All of the results at 3-month follow up were found to be significantly different (p<0.01).

Strengths and limitations

A significant strength of the study was that a range of surgeons carried out the procedures, some of whom had no prior experience with the technology. There was no long-term follow up as most patients were located in rural areas, so only short-term safety and efficacy could be recorded. These results showed consistency with 3-month results reported in previous studies. The study did not include questions related to sexual function.

Sustainability

The company claims the technology will reduce energy consumption and resource use by reducing length of hospital stay and operating time. There is no published evidence to support these claims.

Recent and ongoing studies