Dr. Elterman discusses Rezum and Aquablation for patients with BPH

At the 2021 American Urological Association annual meeting, Dean Elterman, MD, MSc, FRCSC, presented the studies “Rezūm water vapor therapy for large volume (≥80 mL) benign prostatic enlargement: large, multi-center cohort,”1 and “Pooled analysis of bladder function post-Aquablation.”2

In these studies, the Rezum water vapor and Aquablation benign prostatic hyperplasia (BPH) treatments were investigated by Elterman and his co-authors for their efficacy in minimizing symptoms associated with BPH and increasing the quality of life for large cohorts of patients receiving care in Canada. Elterman is an associate professor of urology at the University of Toronto and an attending urologist at the University Health Network, Toronto, Canada.

Rezum water vapor therapy (MP01-08)

Could you discuss the background for the study?

This study looks at Rezum water vapor thermal therapy for prostate enlargement in a cohort of men who have very large prostates, measuring 80 mL or greater. Rezum has been extensively studied and typically used in prostates that are between 30 to 80 mL, and there really aren’t a lot of data available in these large glands. So, we developed a prospective registry to look at these patients moving ahead. At a multicenter study in Canada, we were able to treat over 86 patients during a year-and-a-half period who had prostates that were bigger than 80 mL. The average prostate size was 104 mL, ranging from 80 up to 160 mL. The majority of them had a middle lobe—about 65%—and about 20 patients had previous episodes of retention.

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

There were a lot of unknown variables about how men with these very large prostates would do with this Rezum water vapor therapy. There were a couple notable findings. The first is that the procedures were very quick. The average time to do a procedure was less than 6 minutes, and the range was between about 2.5 minutes up to 14 minutes. If these were performed surgically, they would take well over 1 hour, maybe 2 hours, so it's a significant time reduction. We also found that these men needed catheters in a little bit longer, so we left them in, on average, just shy of 12 days.

However, the results were really impressive. We saw very similar improvements in International Prostate Symptom Score, from a baseline of around 21 all the way down to a score of 8 by 12 months, and we also saw a significant improvement in quality of life. Additionally, we found great improvement in flow rate and post-void residual. So, we're seeing the same types of results that we saw in the regular or smaller gland study—30 to 80 mL—in these very large prostates.

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

This study really demonstrates, for one of the first times in the largest cohort of men ever studied, that Rezum water vapor thermal therapy is a viable option to treat men with very large prostates bigger than 80 mL. It has very low problems in terms of adverse events. It was very safe and also very effective. These, often seen as challenging cases, can be done in an outpatient setting and an office setting very quickly, very safely. And we're seeing very good, robust improvements in BPH parameters as we would see in smaller sized prostates.

Is there anything else you feel our audience should know about the findings?

These are only 1-year findings, and it does take time for these data to mature. The Rezum pivotal study has already been followed out for 5 years, but I do anticipate based on these early 1-year results, that these men with very large prostates should continue to have very good durable outcomes over the years to come.

Aquablation therapy (MP01-11)

Could you discuss the background for this study?

This study was a meta-analysis of individual data of functional outcomes following Aquablation in various prostate anatomies. Aquablation is a novel surgical treatment for BPH whereby we use real-time imaging and water vapor jets to ablate and remove prostate tissue very quickly. The goal was to really evaluate the functional outcomes based on a variety of factors, including how big the prostates were, whether they're smaller or bigger than 100 g, and also whether or not they had middle lobes. What was unique is that we had individual patient data from 4 prospective global clinical trials, so we were able to look at things like IPSS, surgical retreatment rates, and urine flow studies on the individual patient level. We had more than 400 patients who were enrolled in the WATER study (NCT02505919), the WATER II study (NCT03123250), the FRANCAIS WATER study, which was the French study, and the OPEN WATER study. We were able to analyze them based on their prostate size and whether they had a middle lobe.

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

What's really unique is that we were able to have 4 very large clinical trials, and have the data of each individual patient. What we found was that every subgroup, whether they were less than or greater than 100 mL, or whether they had an obstructive median lobe or didn't have a median lobe, all showed significant improvements in their IPSS, quality of life, maximum flow rate, and postvoid residual volume, regardless of their subcategory. And in fact, when we looked at their individual IPSS questions, we saw similar improvements in terms of whether they had storage symptoms or voiding symptoms, regardless of whether they had a smaller prostate less than 100, or a bigger prostate greater than 100, or whether they had a middle lobe or not.

What would you say is the take-home message for the practicing urologist?

The take-home message here is that based on over 400 patients who were included in 4 different prospective studies, we were able to see that Aquablation does improve urinary symptoms and functional outcomes, regardless of whether prostate volumes are greater than 100 mL or less than, or whether they have a middle lobe or not. The idea that Aquablation treats any size and any shape of prostate really does seem to hold true for these cohorts of patients.

Is there anything else you feel our audience should know about the findings?

Looking at Aquablation as a technology that has revolutionized how we see prostates in real time during the operation and are able to speed up the operation using the waterjet, we see very good outcomes. We see improvements in IPSS up to 16 points, we see maximum flow rates over 20 mL per second, and we see significant improvements in quality of life. And notably, we see preservation of ejaculatory function in 90% of men, and erectile function preserved in 100% of men. When we're looking at all these different technologies and checking off the boxes, it does appear that Aquablation really does treat a wide range of prostates.

With several new minimally invasive treatment options available, can you describe your patient selection process?

My patient selection process for BPH treatments can be a little bit cumbersome and lengthy, but that's really because for the first time ever, we have so many different options available to men. We have minimally invasive, office-based therapies currently available, including the UroLift, the Rezum, and now the iTind, the temporary implantable nitinol device. We also now have surgical options which are minimally invasive, or a change on the tried-and-true transurethral resection of the prostate. We have Aquablation as well. A few factors to consider when selecting patients include 1: prostate volume. Number 2 is prostate anatomy—whether they have an obstructing medial middle lobe. Third is patient values and priorities. What is important to them? Do they want something that's done in an office setting? Do they care about the type of anesthesia or how long of a catheter? Duration after the procedure is also important to them and we should consider whether they want preservation of sexual function or ejaculatory function. We go through a list with patients to decide what is important to them and to help them rank factors so that they can come to a decision about which option they want to choose.

Are you performing Rezum and Aquablation in the office or a different setting? Are there any challenges to performing these in the office?

Rezum falls under the category of minimally invasive surgical therapies, or MISTS. These can definitely be done in an office setting with local anesthesia or light sedation. Aquablation is a procedure done in an operating room. It is evolving in terms of being able to change it to a day case, so patients can go home the same day after an Aquablation. They both use water, but in different ways. And so, Rezum is office-based and Aquablation is operating-room-based. One is minimally invasive and the other is more a surgical management of BPH.


1. Elterman D, Bhojani N, Chughtai B, Zorn KC. REZŪM water vapor therapy for large volume (≥80 ml) benign prostatic enlargement: large, multi-center cohort. Paper presented during the 2021 American Urological Association annual meeting. September 10-13; virtual. Abstract MP01-08

2. Elterman D, Gilling P, Roehrborn C, et al. Pooled analysis of bladder function post-Aquablation. Paper presented during the 2021 American Urological Association annual meeting. September 10-13; virtual. Abstract MP01-11