Aquablation demonstrates success in large prostates

For patients with large prostate glands who have lower urinary tract symptoms secondary to BPH, surgical treatment options are limited.

In a recent study presented at the 2021 American Urological Association Annual Meeting,¹ Naeem Bhojani, MD, FRCSC, David-Dan Nguyen, and co-authors, reported the favorable 3-year results of ongoing Aquablation research specifically involving patients with large prostates. Bhojani is a urologist at the University of Montreal Health Care Center (CHUM) and an associate professor in the department of surgery at the University of Montreal, and Nguyen is a medical student at McGill University, Montreal, Canada.

Please discuss the background for this study.

Nguyen: The background in this study is that in previous pooled analyses of Aquablation clinical trials by our group, we've shown that the short-term effectiveness of Aquablation is independent of prostate size, and is associated with a smooth learning curve. We looked at 1-year and 2-year data, and now we want to look at 3-year data to understand the durability of the treatment at 36 months. The main idea is to build on the work that we previously published looking at 1-year and 2-year data, focusing this time more on the durable outcomes.

Bhojani: The key to what David-Dan is saying is that we're looking at prostate volumes between 30 g all the way up to 150 g. So, we're really trying to compare treating smaller glands and bigger glands with this technology to demonstrate its effectiveness.

What were some of the notable findings? Were any of them surprising to you and your co-authors?

Nguyen: Since we started these analyses comparing Aquablation in smaller prostates and in larger glands, we kept finding that the outcomes are very similar between both groups. That has always been very impressive for me, as someone who has reviewed the literature for different projects on BPH surgery. I keep noticing in other studies that larger prostate glands are not associated with the same outcomes than the smaller glands. It doesn't seem to be the case for Aquablation. I think specifically with the 3-year follow up data, what I found the most interesting is the durability outcomes with regards to BPH medication-free status and surgical retreatment status. In WATER (NCT02505919), 98% of treated patients were BPH medication-free at 3 years and 96% were free from surgical retreatment. Very similarly, in WATER II (NCT03123250) with larger prostate glands, 94% were BPH medication-free and 97% were free from surgical retreatment. So, that's very interesting data that was questioned initially when Aquablation was coming to the market, the durability aspect of it.

Bhojani: I think he's absolutely correct. The definition of retreatment is still up in the air. We're not sure if we're talking about medication or surgical retreatment, but the cleanest definition of retreatment would be surgical retreatment. And so, as David-Dan said, the surgical retreatment rate is quite low in these studies, even in prostates up to 150 g. This has to be taken with a grain of salt because we only have 3-year data for now, so I think time will tell if this trend maintains but so far it looks great.

One notable finding is the maintenance of ejaculation. I think this is an important concept. We did a study where we looked at what was important to patients when they were undergoing surgery for BPH. Ninety-five percent of them were very concerned about erectile function, including ejaculatory function. The majority of treatments out there don't allow the maintenance of ejaculation after surgery, whereas here, we're at 90% for the small glands. More importantly, and what was surprising to us was that 81% of the men who had prostates above 80 g, on average 100 g, were able to maintain their antegrade ejaculation. When you look at prostates above 80 g, there's no other treatment out there that can allow for this. All the rest of the treatments—enucleation, GreenLight, open prostatectomy, robotic prostatectomy—will all lead to significant problems with ejaculation.

With so many treatment options available, what is your patient selection process like for patients with BPH?

Bhojani: We thought about this about 2 years ago, and we saw that the number of options available to patients was increasing significantly. So, we created a group of experts in the field, and we decided to create a BPH surgical decision aid. This is something that's extremely important for patients to have. It's a really exciting time for patients who have to deal with BPH and have to possibly undergo surgery, because there's so many options. And each option has advantages and disadvantages, and it's very difficult for patients to determine what's the best surgical option for them. It's difficult for urologists as well. We created this decision aid, which took over a year. We've alpha tested it. It's available free of charge to patients and to urologists, and it includes all guideline-approved surgical options for BPH. It goes through each option in detail, gives a lot of information and tests to see if the patient understood what he/she read. It then tries to help them make a decision based on their objectives and understand what's important to them because each patient is different. I'd like to mention also that when we created this decision aid we had 2 patient partners, so we really tried to make it all-encompassing, hoping to help with the shared decision-making between the patient and the urologist. It's available on the Canadian Urologic Association website, free of charge. It's electronic and we're improving it as much as we can every day.

How is the learning curve for Aquablation?

Nguyen: Very interestingly, at the 2021 American Urological Association Annual Meeting, there was an abstract by another group that looked at the learning curve of Aquablation specifically.² Trifecta was one of the outcomes they looked at, and it was the combination of operative time below 60 minutes, hemoglobin drop under 2 units, and low-grade 2 plus the 90 day complication. And they found that a 50% Trifecta success is seen after 5 cases. They also looked at the Pentafecta outcome, where they added reduction in International Prostate Symptom Score and ejaculatory dysfunction outcomes up to 1 year. They found that after 38 cases, a 50% Pentafecta was achieved with Aquablation. Dr Bhojani obviously knows more than I do with regards to other technologies, but my impression is that it is a very short learning curve to achieve very good outcomes.

Bhojani: When you talk about large glands, the learning curve can be very steep, especially if you're going to learn a enucleation procedure. And so, this was something we looked at when we did the WATER II study, which was glands between 80 and 150 g. The learning curve was 1 maximum 2 cases. So, for most of the patients who were enrolled, the urologist had never performed an Aquablation case. Because of the fact that you have the rectal ultrasound, live ultrasound, and endoscopic views and it's robotically executed. You do all the planning on a flat screen television and it's very easy to use. As urologists, we're all very comfortable with the transrectal ultrasound image. Really, the learning curve is very short, even for these very large glands.

What is the take-home message for the practicing urologist?

Bhojani: There are a number of important things that the practicing urologist should know. One is that this is a very innovative technology that really allows for standardizing the treatment of BPH from small up to large glands. There are a number of significant advantages of this new technology, including the maintenance of antegrade ejaculation, the short operative time, and the exceptional outcomes postoperatively for the patient. I think that it's something that is only going to improve with time, but people should understand that we're at 3-year data still. This is, in my opinion, another surgical option that we can offer to our patients. It doesn't have to be the only one, but it does check a lot of boxes, being that it can treat all different sizes and it has that maintenance of sexual function. It’s an excellent technology. Moving forward, it should be part of our BPH surgical arsenal.

References

1. Nguyen DD, Zorn KC, Bhojani N on behalf of the WATER and WATERII investigators. WATER vs WATER II: Three year comparison of Aquablation therapy for benign prostatic hyperplasia. Paper presented at: 2021 American Urological Association Annual Meeting; September 10-13, 2021; virtual. Abstract PD23-07

2. Nasrallah A, Rijo E, Labban M, et al. The Aquablation surgical technique learning curve: A multicenter study. Paper presented at: 2021 American Urological Association Annual Meeting; September 10-13, 2021; virtual. Abstract MP09-01