TULSA is a minimally invasive MRI-controlled technology, emitting directional high-intensity ultrasound from within the prostate under real-time MRI-thermometry feedback control, for conformal ablation of patient-specific prostate boundaries while sparing surrounding anatomy.
A previous Phase I study of TULSA delivered using a conservative safety margin 3 mm inside the prostate capsule demonstrated safety and ablation precision in 30 patients with low-intermediate risk prostate cancer.
The TACT trial intended to enroll 110 men with biopsy-proven organ-confined prostate cancer, aged 45-80, with ≤ cT2b, PSA ≤ 15 ng/ml, Gleason Score ≤ 3+4, across 13 centers in the USA, Canada, and Europe. MRI-guided TULSA was delivered with the intent of whole-gland ablation to the target boundary traced at the prostate capsule. The primary efficacy endpoint was the proportion of patients achieving a PSA reduction of ≥ 75%, with secondary endpoints of 12-month biopsy and prostate volume reduction. The primary safety endpoint was the frequency and severity of adverse events in the first 12 months. Secondary quality of life endpoints included urinary incontinence (pads), erectile dysfunction (IIEF-5), IIEF-15, IPSS, and EPIC-50.
The study enrolled 115 patients from September 2016 to February 2018. Pre-treatment median (IQR) age was 64 (59-69) years, PSA 6.3 (5.0-8.3) ng/ml, with 39% Gleason 6 and 61% Gleason 7 prostate cancer. There were 34% of patients with low-risk disease and 66% with intermediate-risk disease. The median prostate volume was 34 cc (range 15-88cc). There was no rectal injury or fistula, no urinary incontinence > Grade 1, and no Grade ≥ 4 adverse events. Serious attributable AEs included two patients with urinary retention (treated with catheterization/antibiotics), two with culture-proven UTI, and one with epididymitis (treated with medications/antibiotics), one with urine extravasation into abdomen (treated with catheterization/drainage), one with ileus (secondary to medication), and one with a DVT (treated with heparin). Among these patients, the median PSA reduction was 95% with a median PSA nadir of 0.36 ng/ml (IQR 0.16-0.60), with 95% of patients meeting the endpoint of ≥ 75% reduction. Currently, the number of patients with 12-month quality of life data is not yet large enough to assess.
Dr. Klotz concluded that the preliminary results of the TACT Pivotal study of MRI-guided TULSA for whole-gland ablation in patients with localized prostate cancer showed that 95% of patients met the primary efficacy criteria of ≥ 75% PSA reduction, and the median PSA reduction was 95% from baseline. There was a high degree of safety and a low rate of adverse events. The next steps include assessing further studies recently initiated with regards to targeted therapy, salvage radiation-recurrent therapy, and BPH.
Presented by: Laurence Klotz, MD, FRCSC, Professor, Department of Surgery, University of Toronto, Chief, Division of Urology, Sunnybrook Health Sciences Center, Chair, Canadian Uro-Oncology Group and NCIC GU Site Group, Editor in Chief (founding), Canadian Journal of Urology, Chair, Global GU Oncology Group
Written by: Zachary Klaassen, MD, MSc – Assistant Professor of Urology, Georgia Cancer Center, Augusta University - Medical College of Georgia, Twitter: @zklaassen_md at the 34th European Association of Urology (EAU 2019) #EAU19, conference in Barcelona, Spain, March 15-19, 2019.