Hong Kong Med J 2024 Jun;30(3):227–32 | Epub 10 May 2024
© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
Transurethral water vapour thermal therapy for benign prostatic hyperplasia under local anaesthesia alone: initial experience in Chinese patients
KL Lo, MB, ChB, FRCSEd; Alex Mok, MB, ChB; Ivan CH Ko, MB, ChB; Steffi KK Yuen, MB, BS, FRCSEd; Peter KF Chiu, MB, BS, FRCSEd; CF Ng, MD, FRCSEd
SH Ho Urology Centre, Department of Surgery, The Chinese University of Hong Kong, Hong Kong SAR, China
Corresponding author: Prof CF Ng (ngcf@surgery.cuhk.edu.hk)
 Full paper in PDF
Introduction: This study evaluated the perioperative and early postoperative outcomes of transurethral water vapour thermal therapy (WVTT) under local anaesthesia alone for benign prostatic enlargement in Chinese patients.
Methods: This retrospective review of transurethral WVTT for benign prostatic enlargement focused on 50 Chinese patients who exhibited clinical indications (acute retention of urine or symptomatic lower urinary tract symptoms due to benign prostatic enlargement) for surgical treatment between June 2020 and December 2021 in Hong Kong. Exclusion criteria included active urinary tract problems and urological malignancies. Follow-up was conducted at 3 months postoperatively.
Results: The median patient age was 71.5 years. The mean preoperative prostatic volume was 56.7 mL. The mean operation time was 25.1 minutes. All procedures were performed under local anaesthesia alone. The mean pain scores for transrectal ultrasound probe insertion, transperineal local anaesthesia injection, and transurethral WVTT were 2, 5, and 4, respectively. Forty-nine patients (98%) were discharged on the same day with a urethral catheter. Forty-eight patients (96%) successfully completed a trial without catheter within 3 weeks postoperatively. Five patients (10%) had unplanned hospital admission within 30 days postoperatively due to surgical complications (Clavien–Dindo grade 1).
Conclusion: Transurethral WVTT, an advanced surgical treatment for benign prostatic enlargement, is a safe procedure that relieves lower urinary tract symptoms with minimal hospital stay. It can be performed in an office-based setting under local anaesthesia, maximising utilisation of the surgical theatre.
New knowledge added by this study
  • This is the first study concerning the efficacy and safety profile of water vapour thermal therapy (WVTT) in Asian patients. It can relieve lower urinary tract symptoms with minimal hospital stay.
  • This is the first study of WVTT in an office-based setting under local anaesthesia, maximising utilisation of the surgical theatre.
Implications for clinical practice or policy
  • Water vapour thermal therapy is an effective and safe alternative for patients who have high surgical risk of benign prostatic enlargement under general or spinal anaesthesia.
Benign prostatic hyperplasia (BPH) is characterised by a non-malignant growth in the prostate gland that can cause a wide range of lower urinary tract symptoms (LUTS). These symptoms can greatly reduce a patient’s quality of life (QoL) and may eventually lead to acute retention of urine (AROU).
Current standard treatments for BPH include conservative, pharmacological, and surgical approaches. For patients who fail to successfully complete a trial without catheter (TWOC) after AROU secondary to BPH, surgical intervention remains the main therapeutic approach. Surgical treatment options for BPH have evolved from electrosurgical resection to enucleation, ablation of the prostate, and other techniques.1 Transurethral resection of the prostate (TURP), first performed over 90 years ago, continues to be regarded as the gold standard for the treatment of BPH with prostatic volumes of 30 to 80 mL.2 Although TURP results in statistically significant improvements in symptom scores and maximum urinary flow rate (Qmax), it has some limitations. Perioperative morbidities and complications of TURP include infection, bleeding, urinary retention, incontinence, urethral stricture, erectile dysfunction, and ejaculatory dysfunction. Additionally, TURP requires general or spinal anaesthesia and postoperative hospitalisation. Through technological advancements, several minimally invasive procedures (eg, UroLift and prostatic artery embolisation) have been developed for specific groups of patients with BPH to minimise the aforementioned limitations.3 4 5 Among these new-generation BPH surgical approaches, transurethral water vapour thermal therapy (WVTT) provides some of the best surgical outcomes.
Transurethral WVTT uses the thermodynamic principle of convective energy transfer, whereas other techniques (eg, transurethral microwave thermotherapy or transurethral needle ablation of the prostate) involve conductive heat transfer.6 The thermal therapy system consists of a generator with a radiofrequency power supply that creates water vapour from sterile water, as well as a disposable transurethral delivery device. The tip of the delivery device contains an 18-gauge needle with 12 small emitter holes circumferentially arranged for water vapour dispersion into the targeted prostatic tissue. The release of thermal energy causes tissue necrosis. The most important characteristic of this technique is that, during treatment of the transitional zone, energy is only deposited within this specific region of the prostate. Reviews of histological evidence and magnetic resonance images have revealed that thermal lesions are limited to the transitional zone without affecting the peripheral zone, bladder, rectum, or striated urinary sphincter.7 8 At 6 months after treatment, the total prostatic volume is reduced by 28.9% and the resolution of thermal lesions, as determined by gadolinium-enhanced magnetic resonance imaging, is almost complete.8
A pilot study showed that transurethral WVTT can serve as a safe and effective treatment in men with LUTS due to BPH.8 In the first multicentre, randomised controlled study, 197 men were enrolled and randomised in a 2:1 ratio to treatment with the transurethral WVTT or a sham procedure.9 The sham procedure consisted of rigid cystoscopy with sound effects that mimicked the thermal treatment. The primary efficacy endpoint was met at 3 months: relief of symptoms, measured as a change in International Prostate Symptom Score (IPSS), was detected in 50% of patients in the thermal treatment group compared with 20% of patients in the sham procedure group (P<0.0001). In the thermal treatment group, the Qmax increased by 63%—from 9.9 mL/s to 16.1 mL/s (P<0.0001)—after 3 months. This clinical benefit was sustained throughout the study period, with a 54% improvement at the 12-month follow-up. In the most recent update regarding 5-year outcomes, the improvement in voiding (as measured by IPSS and uroflowmetry) had persisted for 5 years, with a surgical retreatment rate of 4.4%.10
Thus far, studies of transurethral WVTT for BPH have mainly focused on Caucasian populations. To provide information regarding its tolerability and effectiveness in the Chinese population, this study investigated the safety profile and efficacy of transurethral WVTT under local anaesthesia alone for BPH among Chinese patients in Hong Kong.
Study protocol
This retrospective study investigated transurethral WVTT for benign prostatic enlargement. The inclusion criteria included Chinese ethnicity and clinical indications for surgical treatment, including AROU or symptomatic LUTS due to benign prostatic enlargement. Exclusion criteria included active urinary tract problems such as infection, bleeding disorder, bladder pathologies (eg, bladder stones and neurogenic bladder), and urethral stricture, as well as urological malignancies including bladder and prostate cancer.
The procedure was performed with perioperative antibiotic prophylaxis. Patients were placed in the dorsal lithotomy position. After local anaesthesia, cystoscopy was performed to assess the anatomy of the bladder and prostate. A specialised handpiece with an optical lens was inserted under direct visual guidance into the prostate channel. Treatment began with the needle tip visually positioned and inserted approximately 1 cm distal to the bladder neck. Each treatment lasted for 9 seconds. After 9 seconds, an audible signal was produced by the system and the treatment needle was retracted. The handpiece was then repositioned 1 cm distal to the previous treatment site; repositioning was repeated until reaching a treatment site immediately proximal to the verumontanum. During each water vapour injection, the majority of the targeted tissue was treated. All treatment cycles involving one lateral lobe were completed as a group to utilise residual heat from prior treatments involving that lobe. Subsequently, the contralateral lateral lobe was treated in a similar manner. An enlarged median lobe could be treated by positioning the needle at a 45-degree angle towards the targeted lobe using the same technique. After the procedure, a 14-Fr Foley catheter was inserted. A 1-week course of antibiotic treatment was administered after surgery.10 Patients were discharged with the urethral catheter and readmitted for a TWOC at approximately 1 to 2 weeks after surgery. Upon satisfactory completion of the TWOC, patients were scheduled for follow-up at 3 months postoperatively.
Statistical analysis
Preoperative parameters and perioperative outcomes were collected and tabulated using SPSS software (Windows version 28.0; IBM Corp, Armonk [NY], United States). Descriptive statistics were used to summarise the demographic data and perioperative patient characteristics. Paired sample t tests were used to compare continuous variables with normal distributions; the Mann-Whitney U test was used to compare continuous variables with skewed distributions, and the Chi squared test was used to compare categorical variables. Two-sided P values of <0.05 were considered statistically significant.
Between June 2020 and December 2021, 50 eligible patients were included in this study. The median age was 71.5 years (interquartile range [IQR]=64-75.25). In terms of indications, 27 patients (54%) had symptomatic BPH, 13 patients (26%) had AROU with a urethral catheter, and 10 patients (20%) had AROU without a urethral catheter. Of the 50 patients, 39 (78%) were categorised as American Society of Anesthesiologists class 2, whereas the remaining 11 were categorised as class 3. Most patients (68%) did not use any antiplatelet or anticoagulant therapy. The numbers of patients using aspirin, clopidogrel, dual antiplatelet therapy, and apixaban were 11 (22%), three (6%), one (2%), and one (2%), respectively. All antiplatelet and anticoagulant agents were temporarily discontinued before the operation (Table 1).

Table 1. Use of antiplatelet or anticoagulant therapy (n=50)
The mean preoperative prostatic volume was 56.7 mL (standard deviation [SD]=24.6; range, 29.2-119.0). The mean operation time was 25.1 minutes (SD=8.4). All procedures were conducted under local anaesthesia alone. Lignocaine 1% with adrenaline was injected into the periprostatic space using a transperineal approach. The mean pain scores for transrectal ultrasound probe insertion, transperineal local anaesthesia injection, and transurethral WVTT were 2, 5, and 4, respectively.
Postoperative course
Only one patient (2%) required bladder irrigation for 5 days postoperatively; that patient had been taking apixaban before surgery. All other patients were discharged on the same day with a urethral catheter. A TWOC was planned at around 1 week (for the AROU without urethral catheter or symptomatic BPH group) to 2 weeks (for the AROU with urethral catheter group) after surgery. Forty-eight patients (96%) in our study successfully completed a TWOC within 3 weeks postoperatively; the median time was 7 days (IQR=7-14). The median successful TWOC times were 14 days (IQR=8-21) for the AROU with urethral catheter group and 7 days (IQR=7-12) for the AROU without urethral catheter or symptomatic BPH group. Two patients (4%) with an initially unsuccessful TWOC began temporary clean intermittent self-catheterisation; they were subsequently weaned from this management approach on postoperative days 40 and 45, respectively.
Five patients (10%) had unplanned hospital admission within 30 days postoperatively due to surgical complications (Clavien–Dindo grade 1). The reasons for readmission are listed in Table 2.

Table 2. Reasons for readmission (n=50)
There were significant differences in preoperative and 3-month postoperative parameters, including prostate-specific antigen level, post-void residual urine (PVRU) level, Qmax, IPSS, and QoL assessment. Table 3 shows the medians and IQRs of these data. As indicated in Table 4, the mean differences in PVRU, Qmax, IPSS, and QoL score were -41 mL (SD=107), +6.6 mL/s (SD=5.4), -10.9 points (SD=5.8), and -2.2 points (SD=1.5), respectively.

Table 3. Descriptive statistics of preoperative and postoperative parameters

Table 4. Mean differences of parameters 3 months after the procedure
No patients in this study exhibited de novo retrograde ejaculation or stress urinary incontinence at 3 months postoperatively. However, there were three reported cases (6%) of new-onset erectile dysfunction postoperatively. All three patients had temporary erectile dysfunction that resolved within 6 months postoperatively without requiring medication.
Our study is the first to focus on the application of transurethral WVTT (Rezūm therapy) under local anaesthesia alone among Chinese men with BPH. Our results demonstrated clinically significant outcomes comparable to other treatments for BPH. Transurethral WVTT provided effective symptomatic improvement, as illustrated by a decrease in PVRU of 41 mL, an increase in Qmax of 6.6 mL/s, and a substantial decrease in IPSS of 10.9 at the 3-month follow-up (Table 4). These results were also comparable to outcomes in a recent international study of this therapy.10 The postoperative outcome was favourable, with a successful TWOC rate of 96% within 3 weeks postoperatively. Moreover, all patients with urethral catheters before surgery successfully completed a TWOC after transurethral WVTT. The median successful TWOC time was 7 days postoperatively. However, compared with data from other studies (4.1 to 5 days),11 12 our centre had a longer duration of catheterisation, which could be explained by our centre’s policy of scheduling a TWOC on postoperative days 7 and 14 for patients without and with a urethral catheter before surgery, respectively. Five patients were readmitted within 30 days after surgery due to haematuria, post-obstructive diuresis, recurrent AROU, and urinary tract infection with AROU (Table 2). All were uneventfully discharged without further readmission; none of them developed postoperative urinary incontinence. Three patients reported de novo erectile dysfunction, higher than the rate observed in the recent international study.10 However, the rate remained significantly lower than that associated with TURP.13 Considering the minimally invasive nature of this procedure, it could revolutionise future management of BPH.
The current management algorithm for BPH does not include transurethral WVTT as a first-line treatment due to the relative lack of evidence regarding its mid- to long-term efficacy and safety.2 However, it has considerable potential in the management of BPH because of unique advantages compared with TURP. Transurethral WVTT can be an office-based procedure with a short learning curve. If a surgeon completes 10 cases of transurethral WVTT under supervision, he/she will become independent from a surgical trainer. Because BPH is a particularly common urological disease and often requires surgical management,14 the minimally invasive nature of transurethral WVTT can help reduce the number of patients waiting for operations in overcrowded hospital facilities. The results of our study provide initial evidence that transurethral WVTT is well-tolerated among patients under local anaesthesia alone. We did not administer any sedation to the patients because they might move during the operation, resulting in a high risk of water vapour leakage. Such leakage would lead to inadequate treatment.
In Hong Kong, total health costs represent about 19% of the total government budget,15 and public in-patient health costs in 2021/2022 constituted 32% of total health costs.16 Operation time is one of the most important factors affecting in-patient costs. According to a meta-analysis by Mamoulakis et al17 in 2009, the mean operation time for TURP ranged from 39 to 79 minutes. In the present study, the mean operation time was 25.1 minutes. Thus far, no studies have directly assessed the cost-effectiveness of transurethral WVTT in the Chinese population. In the United States, a cost-effectiveness analysis of six therapies for BPH, published in 2018,18 showed that transurethral WVTT was more cost-effective than other minimally invasive therapies, such as combination medical treatment and UroLift. Moreover, McVary et al10 reported that the 5-year retreatment rate after transurethral WVTT was 4.4%, which was significantly lower than that after UroLift therapy (13.6%) reported by Roehrborn et al.5
Notably, transurethral WVTT leads to lower incidences of bleeding, urgency, urge incontinence, and ejaculatory dysfunction compared with TURP.19 The more favourable side-effect profile has resulted in considerable interest concerning its potential to replace TURP as the first-line surgical treatment in the future. No head-to-head trials have compared other surgical modalities with transurethral WVTT. Indirect comparison through a meta-analysis revealed that TURP outperformed transurethral WVTT by providing greater relief of LUTS,19 although it carried a greater cost and higher complication rate.18 Although pharmacological treatment is currently the first-line treatment for moderate to severe LUTS, it is associated with complications such as dizziness, postural hypotension, reduced libido, and erectile dysfunction. Gupta et al20 compared standard medical therapy with transurethral WVTT using cohort data from the MTOPS trial (Medical Therapy of Prostatic Symptoms); they showed that transurethral WVTT had superior outcomes in terms of QoL, IPSS, and prostatic volume reduction. Considering these advantages, transurethral WVTT can be regarded as a first-line treatment option for patients with symptomatic LUTS who prefer a short operation, rather than lifelong pharmacological treatment.
There were some limitations in this study. First, a substantial proportion of our patients had been catheterised preoperatively (74%) and thus could not undergo uroflowmetry studies before the operation. Due to the coronavirus disease 2019 pandemic and the associated community isolation policy, some other patients did not complete uroflowmetry studies. However, all IPSS data were able to be collected via telemedicine, ensuring the inclusion of those data in the analysis. Second, our study did not have a sufficient number of patients to allow subgroup analysis of patients with different indications for transurethral WVTT; future studies should explore treatment outcomes among patients with different indications for transurethral WVTT. Third, our inclusion period was prolonged, partly due to the coronavirus disease 2019 pandemic and partly because transurethral WVTT mainly was regarded as a self-financed item in our centre; these aspects led to some difficulty in accumulating a sufficient number of patients for analysis. Finally, this study used a single-arm design with a relatively short follow-up period; additional studies are needed to assess long-term treatment outcomes and retreatment rates after transurethral WVTT under local anaesthesia alone.
Transurethral WVTT is a safe and effective treatment for benign prostatic hyperplasia in the Chinese population. It can also be conducted in an office setting under local anaesthesia alone, avoiding use of the surgical theatre and its associated costs.
Author contributions
Concept or design: KL Lo, CF Ng.
Acquisition of data: KL Lo.
Analysis or interpretation of data: A Mok, ICH Ko.
Drafting of the manuscript: KL Lo, A Mok, ICH Ko.
Critical revision of the manuscript for important intellectual content: All authors.
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
Conflicts of interest
As an editor of the journal, CF Ng was not involved in the peer review process. Other authors have disclosed no conflicts of interest.
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Ethics approval
This research was approved by the Joint Chinese University of Hong Kong–New Territories East Cluster Clinical Research Ethics Committee, Hong Kong (Ref No.: 2019.662). The patients were treated in accordance with the tenets of the Declaration of Helsinki and have provided written informed consent for all treatments and procedures and consent for publication.
1. Kahokehr A, Gilling PJ. Landmarks in BPH—from aetiology to medical and surgical management. Nat Rev Urol 2014;11:118-22. Crossref
2. Gravas S, Cornu JN, Gacci M, et al. EAU guidelines on management of non-neurogenic male lower urinary tract symptoms (LUTS), incl. benign prostatic obstruction (BPO). 2022. Available from: https://d56bochluxqnz.cloudfront.net/documents/full-guideline/EAU-Guidelines-on-Non-Neurogenic-Male-LUTS-2022.pdf. Accessed 8 May 2024.
3. Teoh JY, Chiu PK, Yee CH, et al. Prostatic artery embolization in treating benign prostatic hyperplasia: a systematic review. Int Urol Nephrol 2017;49:197-203. Crossref
4. Abt D, Hechelhammer L, Müllhaupt G, et al. Comparison of prostatic artery embolisation (PAE) versus transurethral resection of the prostate (TURP) for benign prostatic hyperplasia: randomised, open label, non-inferiority trial. BMJ 2018;361:k2338. Crossref
5. Roehrborn CG, Barkin J, Gange SN, et al. Five-year results of the prospective randomized controlled prostatic urethral L.I.F.T. study. Can J Urol 2017;24:8802-13.
6. Magistro G, Chapple CR, Elhilali M, et al. Emerging minimally invasive treatment options for male lower urinary tract symptoms. Eur Urol 2017;72:986-97. Crossref
7. Dixon CM, Rijo Cedano E, Mynderse LA, Larson TR. Transurethral convective water vapor as a treatment for lower urinary tract symptomatology due to benign prostatic hyperplasia using the Rezūm(®) system: evaluation of acute ablative capabilities in the human prostate. Res Rep Urol 2015;7:13-8. Crossref
8. Mynderse LA, Hanson D, Robb RA, et al. Rezūm system water vapor treatment for lower urinary tract symptoms/benign prostatic hyperplasia: validation of convective thermal energy transfer and characterization with magnetic resonance imaging and 3-dimensional renderings. Urology 2015;86:122-7. Crossref
9. McVary KT, Gange SN, Gittelman MC, et al. Minimally invasive prostate convective water vapor energy ablation: a multicenter, randomized, controlled study for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia. J Urol 2016;195:1529-38. Crossref
10. McVary KT, Gittelman MC, Goldberg KA, et al. Final 5-year outcomes of the multicenter randomized sham-controlled trial of a water vapor thermal therapy for treatment of moderate to severe lower urinary tract symptoms secondary to benign prostatic hyperplasia. J Urol 2021;206:715-24. Crossref
11. Dixon CM, Cedano ER, Pacik D, et al. Two-year results after convective radiofrequency water vapor thermal therapy of symptomatic benign prostatic hyperplasia. Res Rep Urol 2016;8:207-16. Crossref
12. Rowaiee R, Akhras A, Lakshmanan J, Sikafi Z, Janahi F. Rezum therapy for benign prostatic hyperplasia: Dubai’s initial experience. Cureus 2021;13:e18083. Crossref
13. Pavone C, Abbadessa D, Scaduto G, et al. Sexual dysfunctions after transurethral resection of the prostate (TURP): evidence from a retrospective study on 264 patients. Arch Ital Urol Androl 2015;87:8-13. Crossref
14. Lee YJ, Lee JW, Park J, et al. Nationwide incidence and treatment pattern of benign prostatic hyperplasia in Korea. Investig Clin Urol 2016;57:424-30. Crossref
15. Hong Kong SAR Government. The 2023-24 Budget. Budget speech. Available from: https://www.budget.gov.hk/2023/eng/budget30.html. Accessed 5 May 2024.
16. Health Bureau, Hong Kong SAR Government. Hong Kong’s domestic health accounts (DHA) 2021/22. Available from: https://www.healthbureau.gov.hk/statistics/en/dha.htm. Accessed 5 May 2024.
17. Mamoulakis C, Ubbink DT, de la Rosette JJ. Bipolar versus monopolar transurethral resection of the prostate: a systematic review and meta-analysis of randomized controlled trials. Eur Urol 2009;56:798-809. Crossref
18. Ulchaker JC, Martinson MS. Cost-effectiveness analysis of six therapies for the treatment of lower urinary tract symptoms due to benign prostatic hyperplasia. Clinicoecon Outcomes Res 2018;10:29-43. Crossref
19. Tanneru K, Jazayeri SB, Alam MU, et al. An indirect comparison of newer minimally invasive treatments for benign prostatic hyperplasia: a network meta-analysis model. J Endourol 2021;35:409-16. Crossref
20. Gupta N, Rogers T, Holland B, Helo S, Dynda D, McVary KT. Three-year treatment outcomes of water vapor thermal therapy compared to doxazosin, finasteride and combination drug therapy in men with benign prostatic hyperplasia: cohort data from the MTOPS trial. J Urol 2018;200:405-13. Crossref