MP55-18: A national cohort study of cancer outcomes following high-intensity focused ultrasound treatment of clinically localised prostate cancer

Matthew Parry*, Arunan Sujenthiran, Julie Nossiter, Melanie Morris, Brendan Berry, Ajay Aggarwal, Heather Payne, Jan van der Meulen, London, United Kingdom, Noel Clarke, Manchester, United Kingdom

Introduction: Focal high-intensity focused ultrasound (HIFU) has fewer treatment-related side effects compared to radical whole-gland therapy (i.e surgery and radiotherapy) but there are limited data on 5-year cancer control. We therefore aimed to report on 5-year prostate cancer control following HIFU.

Methods: This observational cohort study used linked national cancer registry data, radiotherapy data, administrative hospital data and mortality records of 1,381 men treated with HIFU for clinically localised prostate cancer in England. The primary outcome, failure-free survival (FFS), was defined as freedom from local salvage treatment and cancer-specific mortality. Secondary outcomes were freedom from repeat HIFU, freedom from skeletal-related events (SREs), prostate cancer-specific survival (CSS) and overall survival (OS). Cox regression was used to determine whether baseline characteristics, including age, treatment year, T-stage and cancer grade (in groups ranging from 1 [least aggressive] to 5 [most aggressive]) were associated with with FFS.

Results: The median follow-up was 37 months (IQR 20-62). The median age was 65 years (IQR 59-70) and 81% had a International Society of Urological Pathology (ISUP) grade group of 1 or 2. FFS was 96.5% (95% CI 95.4-97.4%) at 1 year, 86.0% (95% CI 83.7-87.9%) at 3 years and 77.5% (95% CI 74.4-80.3%) at 5 years. 5-year FFS for ISUP grade groups 1-5 were 82.9%, 76.6%, 72.2%, 52.3% and 30.8%, respectively (P <0.001). Freedom from repeat HIFU at 5 years was 79.1% (95% CI 75.7-82.1%). 172 (12.5%), 13 (0.9%) and three (0.2%) men required one, two and three repeat HIFU treatments during follow-up, respectively. Nine men experienced a SRE and there were 44 deaths, 13 of which were related to prostate cancer. CSS was 98.8% (95% CI 98-99%) and OS was 95.9% (95% CI 94.2-97.1%) at 5 years.

Conclusions: These results suggest that about four in five men are free from local salvage treatment and cancer-specific mortality at 5 years. Treatment failure varied significantly according to ISUP grade group indicating patient selection remains key and patients should be appropriately informed with respect to salvage radical treatment.

Source of Funding: M.G.P. was supported by the National Institute of Health Research (DRF-2018-11-ST2-036). T.E.C. was supported by the Medical Research Council (MR/S020470/1). B.B. was partly supported by the NHS National Institute for Health Research through an Academic Clinical Fellowship. H.P. was supported by the University College London Hospitals/University College London Comprehensive Biomedical Research Centre. J.v.d.M. was partly supported by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care North Thames at Bart’s Health NHS Trust. The views expressed in this article are those of the authors and not necessarily those of the NHS, the National Institute for Health Research or the Department of Health and Social Care.