Benign prostatic hyperplasia (BPH) is a very common condition in older men. As the prostate enlarges, it can press on the urethra and make urination difficult. Typical symptoms include a weak urinary stream, frequent urination, getting up at night to urinate, and a feeling that the bladder is not fully empty. When medication is no longer sufficient, surgical removal of the inner part of the prostate ("enucleation") is the recommended treatment.

Two modern laser techniques are used for this operation. Holmium Laser Enucleation of the Prostate (HoLEP) is currently considered the reference standard, with very good long-term results and a low rate of re-operations. Thulium Laser Enucleation of the Prostate (ThuLEP) using a pulsed thulium laser is a newer alternative. Because the laser energy is delivered in short pulses, ThuLEP may allow more precise tissue cutting and better control of bleeding during surgery.

So far, only limited high-quality randomized data directly compare the two techniques, particularly for patient-reported outcomes such as urinary symptoms, continence, and erectile function.

Purpose of the study The HoT-Trial investigates whether ThuLEP is as effective as HoLEP for men who need surgery for an enlarged prostate, and whether there are differences in recovery, complication rates, urinary symptoms, continence, and erectile function after surgery.

Research question Does ThuLEP lead to a similar improvement in lower urinary tract symptoms (LUTS) as HoLEP 12 months after surgery, measured by the change in the International Prostate Symptom Score (IPSS)?

How the study works A total of 150 men aged 18 years or older with clinically relevant BPH, an IPSS of 8 or higher, a prostate volume above 40 ml, and an indication for surgery will take part. Each participant will be randomly assigned (1:1) to either ThuLEP or HoLEP. Participants are blinded to the assigned technique (single-blind design). Both procedures are established, guideline-recommended treatments; taking part in the study does not add any risks beyond standard care.

Before surgery, participants complete standardized questionnaires (IPSS, ICIQ-SF, IIEF) and undergo uroflowmetry and residual urine measurement. Surgery is performed according to randomization. Participants are then followed up in the urology outpatient clinic at discharge and at 3, 6, and 12 months after surgery. The same measurements and questionnaires are repeated at each visit.

Primary outcome Change in IPSS from baseline to 12 months after surgery.

Secondary outcomes Maximum urinary flow rate (Qmax) and post-void residual urine; continence (ICIQ-SF) and erectile function (IIEF); operative time, laser time, blood loss, transfusion rate; catheter indwelling time and length of hospital stay; peri- and postoperative complications graded by the Clavien-Dindo classification; and the rate of re-intervention or re-catheterization within 12 months.

Setting and timeline The study is conducted as a single-center trial at the Department of Urology, Ludwig-Maximilians-University Munich, Germany. Recruitment runs for approximately two years, with up to 12 months of follow-up per participant. The total study period is planned from April 2026 to April 2029.

By directly comparing the two laser enucleation techniques in a randomized setting, the HoT-Trial aims to help patients and physicians choose the most suitable surgical treatment for benign prostatic hyperplasia.

Background and rationale Benign prostatic syndrome (BPS) is among the most frequent urological diseases in older men and a leading cause of treatment-requiring lower urinary tract symptoms (LUTS). For moderately to severely enlarged prostates, endoscopic enucleation procedures have become the surgical gold standard. Holmium Laser Enucleation of the Prostate (HoLEP) is considered the reference technique, with excellent long-term functional outcomes and a low re-intervention rate.

Thulium Laser Enucleation of the Prostate (ThuLEP) using pulsed thulium laser technology (wavelength approximately 2013 nm) has been introduced as an alternative enucleation procedure. The high absorption in water enables precise tissue dissection while allowing effective hemostasis, and the pulsed energy delivery may offer advantages in tissue control, precision, and intraoperative hemostasis. However, adequately powered prospective randomized trials directly comparing ThuLEP and HoLEP remain scarce, and patient-reported outcomes such as IPSS and ICIQ-SF are insufficiently studied.

Objectives The primary objective is to compare the improvement of LUTS between ThuLEP and HoLEP, measured as the change in IPSS from baseline to 12 months postoperatively. Secondary objectives include comparison of functional outcomes (Qmax, post-void residual urine), urinary continence (ICIQ-SF), erectile function (IIEF), perioperative parameters (operative time, laser time, blood loss, catheter indwelling time, length of hospital stay), complication rates (Clavien-Dindo), and re-intervention and re-catheterization rates.

Design Prospective, randomized, single-blind (participant-blinded), interventional comparative trial with 1:1 allocation to ThuLEP or HoLEP. Randomization is performed using sealed envelopes drawn preoperatively. Follow-up duration is 12 months per participant.

Study procedures After establishing the indication for surgical treatment of BPS, patients are screened and informed. Following written informed consent, patients are randomized. Baseline assessment (IPSS, Qmax, post-void residual urine, IIEF, ICIQ-SF) is performed the day before surgery. Surgery is performed according to randomization. Clinical baseline data (laboratory parameters, age, medications, comorbidities) and perioperative data (operative time, resection weight, laser energy) are extracted from operative and medical records. Postoperative assessments are performed at discharge and at 3, 6, and 12 months in the urology outpatient clinic, where patients are scheduled for follow-up visits.

Sample size Sample size calculation is based on the primary endpoint ΔIPSS. Assuming a clinically relevant difference of 5 IPSS points, a standard deviation of 7 points, a power of 80-90%, and a significance level of α = 0.05, approximately 64-86 patients per group are required. Allowing for a 10% drop-out rate, a total of 150 patients will be enrolled.

Risk-benefit Both surgical techniques are established, guideline-concordant treatments of BPS. Participation in the study does not introduce additional procedural risks. A potential benefit is the optimization of individualized treatment strategies for future patients.

Data management Data processing follows medical confidentiality and data protection regulations. Patient data are pseudonymized using an automatically generated code linked to name and date of birth; the decoding key is accessible only to the study team. Data are stored exclusively on secure computers within the hospital network and retained for a maximum of 10 years. No biological material is collected. No data transfer to third parties is planned. Participants may request deletion of their data at any time.

Inclusion Criteria:

• Male, age ≥ 18 years
• Clinically relevant benign prostatic syndrome (BPS) with an established indication for surgical treatment
• International Prostate Symptom Score (IPSS) ≥ 8
• Prostate volume > 40 ml
• Signed written informed consent

Exclusion Criteria:

• Proven or suspected prostate cancer
• Previous surgery of the prostate or urethra
• Neurogenic bladder dysfunction
• Anticoagulation therapy that cannot be paused perioperatively