LAUSR

BACKGROUND MRI-guided transurethral ultrasound ablation (TULSA) uses directional thermal ultrasound under MRI thermometry feedback control for prostatic ablation. We report 12-month outcomes from a prospective multicenter trial (TACT). METHODS 115 men with favorable to intermediate risk prostate cancer across 13 centers were treated with. whole-gland ablation sparing the urethra and apical sphincter. The co-primary 12-month endpoints were safety and efficacy. RESULTS 72 (63%) had GG2 and 77 (67%) had NCCN intermediate-risk disease. Median treatment delivery time was 51 minutes with 98% (IQR 95-99%) thermal coverage of target volume and spatial ablation precision of ±1.4 mm on MRI thermometry. Grade 3 adverse events occurred in 9 (8%) men. The primary endpoint (FDA mandated) of PSA reduction ≥75% was achieved in 110 of 115 (96%) with median PSA reduction of 95% and nadir of 0.34 ng/ml. Median prostate volume decreased from 37 to 3 cc. Among 68 men with pre-treatment GG2, 52 (79%) were free of GG2 disease on 12-month biopsy. Of 111 men with 12-month biopsy data, 72 (65%) had no evidence of cancer. Erections (IIEF Q2 ≥ 2) were maintained/regained in 69 of 92 (75%). Multivariate predictors of persistent GG2 at 12 months included intra-prostatic calcifications at screening, suboptimal MRI thermal coverage of target volume, and a PIRADS ≥ 3 lesion at 12-month MRI (p < 0.05). CONCLUSIONS The TACT study of MRI-guided transurethral ultrasound whole-gland ablation in men with localized prostate cancer demonstrated effective tissue ablation and PSA reduction with low rates of toxicity and residual disease.