Non-inferiority, randomised, open-label clinical trial on the effectiveness of transurethral microwave thermotherapy compared to prostatic artery embolisation in reducing severe lower urinary tract symptoms in men with benign prostatic hyperplasia: study protocol for the TUMT-PAE-1 trial.

Background: One-fourth of men older than 70 years have lower urinary tract symptoms (LUTS) that impair their quality of life. Transurethral resection of the prostate (TURP) is considered the gold standard for surgical treatment of LUTS caused by benign prostatic hyperplasia (BPH) that cannot be managed conservatively or pharmacologically. However, TURP is only an option for patients fit for surgery and can result in complications. Transurethral microwave thermotherapy (TUMT) and prostatic artery embolisation (PAE) are alternative minimally invasive surgical therapies (MISTs) performed in an outpatient setting. Both treatments have shown to reduce LUTS with a similar post-procedure outcome in mean International Prostate Symptom Score (IPSS). It is however still unknown if TUMT and PAE perform equally well as they have never been directly compared in a randomised clinical trial. The objective of this clinical trial is to assess if PAE is non-inferior to TUMT in reducing LUTS secondary to BPH.

Methods: This study is designed as a multicentre, non-inferiority, open-label randomised clinical trial. Patients will be randomised with a 1:1 allocation ratio between treatments. The primary outcome is the IPSS of the two arms after 6 months. The primary outcome will be evaluated using a 95% confidence interval against the predefined non-inferiority margin of + 3 points in IPSS. Secondary objectives include the comparison of patient-reported and functional outcomes at short- and long-term follow-up. We will follow the patients for 5 years to track long-term effect. Assuming a difference in mean IPSS after treatment of 1 point with an SD of 5 and a non-inferiority margin set at the threshold for a clinically non-meaningful difference of + 3 points, the calculated sample size was 100 patients per arm. To compensate for 10% dropout, the study will include 223 patients.

Discussion: In this first randomised clinical trial to compare two MISTs, we expect non-inferiority of PAE to TUMT. The most prominent problems with MIST BPH treatments are the unknown long-term effect and the lack of proper selection of candidates for a specific procedure. With analysis of the secondary outcomes, we aspire to contribute to a better understanding of durability and provide knowledge to guide treatment decisions.

Trial registration: ClinicalTrials.gov NCT05686525. Registered on January 17, 2023, https://clinicaltrials.gov/study/NCT05686525 .