MR-guided Transurethral Ultrasound Ablation (TULSA) with dose escalation to MRI-visible prostate cancer lesions

Tuesday, April 1, 2025

3:36 PM – 3:45 PM CT

Location: Music City Center, 204

Presenting Author(s)

Joseph J. Busch, Jr., MD

Oncological Radiologist
Busch Center, United States

Author/Co-author(s)

KB

Kathy Busch, BS, RT (N), (CT), (MRI), CNMT (PET)

Clinical Manager
Busch Center, United States
RR

Roland Rose, n/a

Imaging Specialist
Busch Center, United States
AS

Amanda Sdrigotti, BS, MS

Manager, Clinical Science
Profound Medical, United States

Purpose: MRI-guided transurethral ultrasound ablation (TULSA) is an interventional MRI procedure for prostate cancer (PCa). Regulatory studies used whole-gland ablation in low to intermediate-risk PCa with a single sweep [1]. We report outcomes of TULSA with dose escalation to MRI-visible lesions concordant to clinically significant histology on targeted biopsy, spanning from low to high-grade PCa.

Materials and Methods: A retrospective analysis included PCa patients with at least 3 months follow-up who underwent TULSA with dose escalation (two or more sweeps) to the index lesion targeted by intraoperative DWI, ADC, and T2-weighted imaging. High-grade patients with negative PSMA-PET were included after counseling. Patients were followed daily for 2 weeks, PSA q3m, with MRI, IPSS, IIEF at 6-9 months. Radiologic recurrence was defined as PI-RR≥4 on mpMRI, or positive PSMA-PET after PI-RR=3. Biochemical recurrence (BCR) was defined as nadir + 2 ng/ml.

Results: 136 patients were identified with median (IQR) age and follow-up duration of 63 (IQR 58-68) years and 11 (9-18) months. Proportions of men with histological grade group 1-5 PCa were: 9%, 52%, 23%, 10%, 7%. PIRADS 4 and 5 MRI lesions were present in 42% and 58% of men. Median prostate volume was 50cc (IQR 37-68, range 12-160). Whole-gland ablation was performed in 60% of men, with uni/bilateral NVB sparing in 13%/25%. The extreme apex was targeted in 27%. PSA nadir after primary treatment was 0.9 (0.3-1.9) ng/mL. 89% (121/136) are free of radiologic and biochemical recurrence, with four patients undergoing repeat TULSA. 1 case with BCR had no imaging follow-up. 8/14 radiologic recurrences are BCR-free and remain on surveillance. 3/14 failures were out-of-field, 4/14 had residual disease near ejaculatory duct sparing which was since discontinued. Failures occurred where either MRI thermometry or ultrasound propagation was compromised by calcifications or motion. Grade 1-2 adverse events in 11 men (LUTS, mild hematuria, bladder spasms) resolved within 4 weeks with oral medication. Three men had Grade 3 events requiring endoscopic intervention (retention/obstruction/stricture). Urinary symptoms (IPSS) were stable. Two men incurred early post-op urine leakage, 100% are pad-free beyond 4 months. 84% maintained erection firmness sufficient for penetration (IIEF Q2≥2).

Conclusion: Customized TULSA with dose escalation to MRI-visible lesions shows promising real-world efficacy and safety. Ongoing optimization of patient selection and technique may further improve treatment across all histologic grades.