Water vapor thermal therapy of lower urinary tract symptoms due to benign prostatic obstruction: efficacy and safety analysis of a real-world cohort of 211 patients

Transurethral resection of the prostate (TURP) is considered the gold standard among various procedures for surgical treatment of lower urinary tract symptoms (LUTS) caused by benign prostatic obstruction (BPO). However, due to changes in demography, surgical therapies are facing an increase in comorbidities leading to challenging surgical and anesthesiological decision making [1, 2]. Consequently, not only among an elderly and a potentially comorbid group of patients but also among the average patient cohort, the demand for minimal-invasive treatment (MIT) modalities is increasing. Water vapor thermal therapy (Rezum) by transurethrally injecting 103 °C water steam into the prostate is one of these MIT options and has demonstrated a beneficial efficacy and safety profile for the treatment of LUTS caused by BPO [3]. Previously published studies have either reported on relatively homogeneous collectives of patients [3‐8] or focused on single specific baseline characteristics such as prostate volume (PV) or preoperative catheterization [9, 10]. To what extent these results can be translated to a real-world cohort—including preoperatively catheterized patients or patients with a large prostate or median lobe—has rarely been investigated yet.

We report short- to long-term efficacy and safety outcomes of Rezum therapy for BPO related to LUTS using an unselected real-world cohort.

Our study results demonstrate a considerable, durable efficacy and safety profile of Rezum water vapor therapy of BPO-related LUTS in a real-world cohort. Our data show a considerable improvement in micturition symptoms with a reduction in IPSS by 54.3% and QoL by 33% already 2 months after treatment. Patients experienced an improvement in IPSS and QoL, which was maintained throughout the follow-up period of 4.5 years, confirming data from prior studies [3–8, 13]. Furthermore, voiding function improved after Rezum: an increase in Qmax by 20.2% was observed only 2 months after treatment, reaching maximum improvement with a 66.7% increase at 4 years after Rezum. Improvement in Qmax has been reported to be at 50–100% in other studies [5–8]. Prostate volume decreased by around 30% after no more than 2 postoperative months, which was maintained throughout the observational period. These results are in line with previously published cohorts [5–9, 13] and magnetic resonance imaging data showing a size reduction of about one-third [14]. Post-void residual volume also decreased early by 57% and was maintained through the observational period.

In the pivotal study of McVary et al. [3], rigid inclusion criteria concerning age (> 50 years), IPSS (≥ 13), Qmax (≤ 15 ml/s) and PV (30–80 ml) were applied, and other research groups had similar inclusion criteria for their patients [6–8]. We present comparable results on micturition symptoms and voiding function, though patients in our series were more heterogeneous with regard to their baseline characteristics. Compared to other real-world data, our study includes more patients over a longer follow-up period [13].

In previously published studies, the duration of postoperative catheterization was between 0 and 7 days [3‐9]. In our series, catheterization time was 5 days in patients without preoperative catheter-dependent urinary retention. Trial void evaluations reported rates of postoperative acute urinary retention between 4.4 and 11.8% [3‐9, 13]. In our cohort, the success rate of first catheter removal was 99% in patients without preoperative catheter-depend urinary retention after a median of 5 days. The catheter-free rate in the subgroup of patients with a preoperative catheter was 66% after a median of 16 days. A recently published study showed a slightly higher rate of 70.3% but after a longer period of time (26 days) [10]. These data suggest that time to first removal should potentially be prolonged in preoperatively catheterized patients. Furthermore, preoperative catheterization significantly increased the risk of an unsuccessful catheter removal potentially indicating the influence of additional causes of voiding dysfunction other than or additionally to BPO.

McVary et al. reported a surgical retreatment rate of 4.4% after 5 years with no statistical difference from the previous 4-year data [4]. In our real-world cohort, the reoperation rate seems to be slightly higher with 5.7% after a median time of 407 days. Interestingly, McVary et al. also reported that the majority of patients were reoperated in the first 2 years. Our cohort included a significant number of preoperatively catheterized patients or patients with a PV ≥ 80 ml or a median lobe. PV ≥ 80 ml seems to increase the risk of reoperation. These results show a conflicting picture compared to recently published data demonstrating a similar efficacy and safety profile independent of PV [9]. On the other hand, patients that had a higher PV also were frequently catheterized preoperatively.

Compared to other MIT methods, such as prostatic urethral lift (PUL) and prostate artery embolization (PAE), Rezum seems to outperform with regard to reoperation rates. As published by Miller et al. [15], reoperation rates are 6% per year after PUL. Following PAE, 21% of patients underwent TURP due to unsatisfying outcomes after 2 years [16]. We see a possible explanation in the lower reoperation rates in patients treated by Rezum compared to PUL and PAE, associated with the ablative nature of Rezum and the possibility of median lobe treatment.

For Aquablation—another MIT in used to treat LUTS associated with BPO—rates of reoperation after 2 years are similar to Rezum [17]. However, complication rates seem to be higher using Aquablation, most likely due to the ablative effect.

30-day complications in Rezum are low, especially no bleeding complications occurred even though one-third of the patients were under anticoagulation or platelet aggregation inhibitors. So far, only one of the previous studies stated to not pause anticoagulation when medically indicated [13] while we continued this medication in all patients. Consequently, we assume that Rezum is a safe procedure for patients under anticoagulation and platelet aggregation inhibitors.

This study is not without limitations. The pragmatic, observational design adds selection bias that may underestimate positive as well as negative outcomes. In addition, there is variability in the duration of follow-up. Some of the patients so far have incomplete data. We assume that patients with the worse outcome are more likely to have perceived more frequent consultations, suggesting a better outcome in the actual patient population. Though indication for Rezum was often an important factor for selecting Rezum as a treatment method in sexually active men, sexual outcome parameters such as ejaculation or erectile dysfunctions were rarely reported and for this reason not presented in this study.

Rezum is an MIT option in a real-world cohort of patients with LUTS secondary to BPO. Micturition symptoms and voiding function improve stably over time. Preoperative catheterization and the presence of a median lobe increase the risk of unsuccessful catheter removal. Further studies are needed to determine and maybe extend patient groups for Rezum and to define the role of Rezum in the range of other BPO treatment options currently available.