Is 36 ml of steam indicated for Rezum (transurethral steam ablation) treatment of Benign Prostatic Hyperplasia (BPH)?

Water Vapor Thermal Therapy (Rezūm) for BPH: Volume of Steam Indicated

For Rezūm treatment of BPH, there is no specific indication for exactly 36 ml of steam; rather, the procedure is indicated for prostates <80g with treatment volume determined by prostate size and anatomy.

Indications for Rezūm Therapy

Rezūm (water vapor thermal therapy) is indicated as a minimally invasive surgical treatment option for men with benign prostatic hyperplasia (BPH) who meet the following criteria:

• Prostate volume less than 80g 1
• Moderate to severe lower urinary tract symptoms (LUTS) related to BPH
• Patients who have failed or are unwilling to continue medical therapy
• Patients concerned with preserving sexual and ejaculatory function

Treatment Protocol and Volume Considerations

The amount of water vapor used during Rezūm treatment is not standardized at exactly 36 ml, but rather is determined by:

1. Prostate size: Larger prostates typically require more injections
2. Anatomical considerations: Presence of median lobe, intravesical protrusion
3. Number of injections needed: Each injection delivers a standardized amount of thermal energy

Studies show that the number of vapor injections varies based on individual patient anatomy:

• In a 2021 multicenter Italian study, median operative time was 10.5 minutes with variable numbers of injections 2
• A 2023 multicenter study demonstrated that patients outside the original clinical trial criteria (including those with larger prostates) required more vapor injections but achieved similar outcomes 3

Efficacy and Outcomes

Rezūm has demonstrated effectiveness for BPH treatment with:

• Significant improvements in International Prostate Symptom Score (IPSS) at 3,6, and 12 months 2, 4
• Improved maximum flow rate (Qmax) and decreased post-void residual (PVR) 5, 4
• Preservation of sexual function, including lower rates of ejaculatory dysfunction compared to TURP 1
• Durable results with sustained improvements at 3-year follow-up 1

Special Considerations

• Larger prostates: Recent evidence suggests Rezūm may be effective even for prostates >80g, though this is outside the current guideline recommendations 4
• Urinary retention: Rezūm has shown effectiveness in treating catheter-dependent urinary retention with an 87.8% success rate at 6 months 5
• Median lobe: Presence of a median lobe is not a contraindication for Rezūm therapy 5

Potential Complications

• Most complications are Clavien-Dindo grade 1-2 (minor)
• Low risk of sexual dysfunction with minimal impact on erectile function
• Temporary catheterization is typically required (median 7 days in one study) 2
• Retreatment rates at 3 years are approximately 4.4% 1

Summary

The volume of steam used in Rezūm therapy is not standardized at exactly 36 ml but is individualized based on prostate anatomy and size. The AUA guidelines indicate Rezūm for prostates <80g with treatment delivered according to the manufacturer's protocol, which involves multiple targeted injections rather than a predetermined total volume of steam.