Initial experience of transurethral ultrasound ablation of the prostate in Asia

要旨

Transurethral ultrasound ablation of the prostate (TULSA) is a novel modality for the treatment of localised prostate cancer.1-4 TULSA uses linear high-frequency ultrasound to heat the prostatic tissue, and the treatment margin is precisely controlled by closed-loop control of ultrasound emission by measuring the temperature of prostatic tissue inside a magnetic resonance imaging (MRI) bore in a real-time manner. The surface of the urethra and the rectal wall are cooled during the treatment.1-4 The pivotal trial in Europe and North America showed significantly low rates of urinary incontinence and erectile dysfunction without compromising cancer control for low and intermediate-risk cancer.4 We herein show our initial experience of TULSA for the first time in Asia. Five men with localised prostate cancer who underwent TULSA and followed for over 1 year are included. There were 4 cases of high-risk cancer and one case of intermediate-risk cancer. Two men underwent whole-gland ablation and three partial ablation. Patients' characteristics and representative MRI images are shown in Table S1 and Figure S1. A Foley catheter was placed after the procedure and was removed the next morning. Patients underwent clean intermittent catheterization (CIC) in case of voiding difficulty. Changes in prostate-specific antigen (PSA) levels, MRI findings at 6 and 12 months after TULSA, prostatic volume measured by MRI, changes in symptoms and quality of life (QOL) using Expanded Prostate Cancer Index Composite5 and SF-12 Health Survey6 were recorded. All patients underwent uneventful TULSA and returned to normal activity immediately. Two patients with whole-gland and one patient with subtotal ablation underwent self CIC for 7–17 days, and two with partial ablation did not require CIC. All patients were pad-free after TULSA. Erectile and ejaculatory functions were preserved in the one patient who was sexually active before TULSA. No complications were observed. PSA remained stable for up to 1 year in four patients (Figure 1). These 4 patients showed negative MRI studies at 6 and 12 months. The mean prostate volume of 5 patients decreased by 47% from 24 mL pre-TULSA to 12 mL at 1 year. One patient with the whole-gland therapy showed PSA relapse at 10 months, and MRI showed tumour recurrence involving the left seminal vesicle with no evidence of metastasis. He did not undergo an MRI before referral and had already been under androgen deprivation therapy (ADT) for 6 months at referral. He was assumed to have had seminal vesicle invasion originally, which was outside the ablation boundary. He underwent a successful salvage radiation therapy of 70Gy and ADT, because TULSA does not preclude any salvage treatments. SF-12 survey showed no significant changes in component summary scores throughout the study period, and the average scores were higher than the Japanese average. We herein showed our initial experience of TULSA in Japanese patients. Cancer control up to 1Y was satisfying in 4 patients. One of the important features of TULSA is that it has a very low rate of urinary incontinence, which has been the most significant unsolved problem after radical prostatectomy.7 Very accurate control of the treatment boundary brings secure ablation of the tissue to the boundary with no damages beyond, as all the patients in our series were continent after TULSA. One patient requested the preservation of erectile and ejaculatory functions, both of which were successfully preserved by unilateral partial ablation while excluding the ejaculatory ducts. Accurate margin control offers a great advantage for patients who seek for retaining their function. TULSA is an incision-free therapy, which can be performed on a single day with a short-term hospitalisation. No decline in QOL was observed, and patients' satisfaction score was considerably high. The prostate swells after heat ablation and the prostatic urethra can be obstructed especially after a whole-gland treatmen

主題