CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-08-14). The draft was written by AI, the existence of all 2 cited sources was verified (1 access-limited, verified via index/summary and marked), and the verdict passed blind grading and adversarial audit. Methodology v0.7.
Verdict No. 2551 · Search date 2026-08-14 · Methodology v0.7

Rezūm water-vapor therapy,
does it really help with Improvement of moderate-to-severe lower urinary tract symptoms caused by benign prostatic hyperplasia?

30-Second Summary
C
Evidence Grade C · 50 · Safety caution
Rezūm substantially improved three-month urinary symptoms versus sham; evidence comes from one trial, with manufacturer sponsorship documented in its follow-up report.
Dysuria, hematuria, urgency, urinary infection, and transient retention have been reported, and catheterization may be required. Urologic assessment of prostate size and retention risk is needed.
What the
research shows
The grade is C. In a sham-controlled trial, 197 men were randomized 136 versus 61; three-month IPSS fell by 11.2±7.6 versus 4.3±6.9 points (P<0.0001). The 6.9-point between-group change corresponds to a large standardized effect of about 0.93. The 2016 pivotal paper's own Funding text could not be checked, but a follow-up report from the same trial states NxThera sponsorship; efficacy included 195 men, giving C with 50 points.
What the
ads claim
The device genuinely creates water vapor to ablate tissue, and the trial genuinely found better three-month symptoms than sham. Those facts do not establish superiority over medication or surgery, nor prevention of retreatment across all prostate sizes.
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Useful facts when choosing a product

  • The device uses radiofrequency-generated water vapor to create thermal lesions in prostatic transition-zone tissue.
  • The trial randomized 197 men, 136 versus 61, and analyzed IPSS efficacy in 195, 134 versus 61.
  • The registered three-month IPSS primary outcome matched the paper, and controls underwent rigid cystoscopy with simulated sounds.
Gap Measurement · Verdict 2551 · C 50
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

McVary KT et al. randomized 197 men aged at least 50 with IPSS at least 13 and prostate volume 30–80 mL in a 2:1 ratio. Controls received rigid cystoscopy with simulated treatment sounds, and three-month IPSS change was the primary endpoint. Efficacy included 195 men, 134 versus 61, while safety included all 197. The 2016 pivotal paper's own Funding text was not accessible. The four-year follow-up from the same trial (PMID 30677455) states, ‘The clinical study was sponsored by NxThera Inc.’ It is follow-up of the same trial and was not counted as replication. Existing BPH verdicts address drugs or transurethral resection; this verdict addresses a transurethral water-vapor ablation device.

02

Why this is classified as C (50)

A large symptom effect was demonstrated against sham, but manufacturer sponsorship documented in a follow-up report from the same trial, one confirmatory trial, and fewer than 200 randomized participants give C with 50 points.

Counterpoint. C does not mean no effect. It reflects a large direct effect supported at a limited and nonindependent evidence level.

Rejudgment record. Cross-check applied — We cross-checked analysis denominators, primary outcome, sham procedure, and registry against the pivotal paper; sponsorship was verified in the four-year follow-up from the same trial.

Scoring profile behind this grade
EndpointPPatient-reported treatment goal - the symptom is the goal
ReplicationR1Single confirmatory trial
IndependenceI0Evidence comes only from manufacturer studies
Effect sizeE+Meets the clinically important threshold

The scoring table and the verdict agree (C).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
Improved urinary symptoms at three monthsCIPSS reduction was 6.9 points greater than with sham.
Superiority to medication or transurethral resection?The pivotal trial used sham control and did not make this direct comparison.

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Study 1Multicenter 2:1 randomized participant-masked sham-controlled trial61The 2016 paper's own Funding text was not verified; the four-year follow-up from the same trial states NxThera Inc. sponsorshipChange from baseline in IPSS at three months−11.2±7.6 versus −4.3±6.9 points, P<0.0001; between-group change difference 6.9 points, standardized difference about 0.93Pivotal sham-controlled symptom trial
Study 2Long-term follow-up report from the same NCT01912339 randomized trial‘The clinical study was sponsored by NxThera Inc.’Four-year symptom durability and retreatmentFollow-up used to verify sponsorship; not counted as separate replicationFollow-up of the same trial
§

Receipt — 2 References

Of 2 cited sources, 1 had limited original-page access (blocked or summary-only) and were verified via index/summary, marked partial; the rest were verified at the original page. As of 2026-08-14.

McVary KT, Gange SN, Gittelman MC, Goldberg KA, 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(5):1529-1538. PMID: 26614889. DOI: 10.1016/j.juro.2015.10.181. NCT01912339.
partial
McVary KT, Rogers T, Roehrborn CG. Rezūm Water Vapor Thermal Therapy for Lower Urinary Tract Symptoms Associated With Benign Prostatic Hyperplasia: 4-Year Results From Randomized Controlled Study. Urology. 2019;126:171-179. PMID: 30677455. DOI: 10.1016/j.urology.2018.12.041.
checked
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-14 · Corrections: none

Cite this verdict

Rezūm water-vapor therapy x improvement of BPH urinary symptoms Evidence Grade C card
[Chamgap] Rezūm water-vapor therapy x improvement of BPH urinary symptoms — Evidence Grade C·50. 2 cited sources checked. Source: https://chamgap.com/en/verdicts/mens/rezum-water-vapor-bph-luts-improvement/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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