Salvage Magnetic Resonance Imaging-guided Transurethral Ultrasound Ablation for Localized Radiorecurrent Prostate Cancer: 12-Month Functional and Oncological Results

Eur Urol Open Sci. 2020 Nov 25:22:79-87. doi: 10.1016/j.euros.2020.10.007. eCollection 2020 Dec.

Abstract

Background: Up to half of all men who undergo primary radiotherapy for localized prostate cancer (PCa) experience local recurrence.

Objective: To evaluate the safety and early functional and oncological outcomes of salvage magnetic resonance imaging-guided transurethral ultrasound ablation (sTULSA) for men with localized radiorecurrent PCa.

Design setting and participants: This prospective, single-center phase 1 study (NCT03350529) enrolled men with biopsy-proven localized PCa recurrence after radiotherapy. Multiparametric magnetic resonance imaging (mpMRI) and 18F prostate-specific membrane antigen-1007 (18F PSMA-1007) positron emission tomography (PET)-computed tomography (CT) were used to confirm organ-confined disease localization. Patients underwent either whole-gland or partial sTULSA, depending on their individual tumor characteristics.

Outcome measurements and statistical analysis: Patients were followed at 3-mo intervals. Adverse events (AEs, Clavien-Dindo scale), functional status questionnaires (Expanded Prostate Cancer Index [EPIC]-26, International Prostate Symptom Score, International Index of Erectile Function-5), uroflowmetry, and prostate-specific antigen (PSA) were assessed at every visit. Disease control was assessed at 1 yr using mpMRI and 18F-PSMA-1007 PET-CT, followed by prostate biopsies.

Results and limitations: Eleven patients (median age 69 yr, interquartile range [IQR] 68-74) underwent sTULSA (3 whole-gland, 8 partial sTULSA) and have completed 12-mo follow-up. Median PSA was 7.6 ng/ml (IQR 4.9-10) and the median time from initial PCa diagnosis to sTULSA was 11 yr (IQR 9.5-13). One grade 3 and three grade 2 AEs were reported, related to urinary retention and infection. Patients reported a modest degradation in functional status, most significantly a 20% decline in the EPIC-26 irritative/obstructive domain at 12 mo. A decline in maximum flow rate (24%) was also observed. At 1 yr, 10/11 patients were free of any PCa in the targeted ablation zone, with two out-of-field recurrences. Limitations include the nonrandomized design, limited sample size, and short-term oncological outcomes.

Conclusions: sTULSA appears to be safe and feasible for ablation of radiorecurrent PCa, offering encouraging preliminary oncological control.

Patient summary: We present safety and 1-yr functional and oncological outcomes of magnetic resonance imaging-guided transurethral ultrasound ablation (TULSA) as a salvage treatment for local prostate cancer recurrence after primary radiation. Salvage TULSA is safe and shows the ability to effectively ablate prostate cancer recurrence, with acceptable toxicity.

Keywords: Biochemical recurrence; Clinical trial; Radiation therapy; Salvage intervention; Therapeutic ultrasound; Thermal ablation.