LBA 32 - Efficacy of Radical Prostatectomy Versus Stereotactic Body Radiotherapy (SBRT) for Localised Prostate Cancer: Results from an international Phase III Randomised Controlled Trial (PACE - A)
Presenter(s)
N. van As1, J. Patel2, A. Tree3, P. Ostler4, H. Van Der Voet5, D. Ford6, S. Tolan7, P. Wells8, R. I. Mahmood9, M. Winkler10, A. K. Chan11, A. Thompson1, C. Ogden12, O. Naismith13, D. Price14, J. Pugh3, S. Brown3, G. Manning3, F. Cafferty15, and E. Hall3; 1The Royal Marsden NHS Foundation Trust, London, United Kingdom, 2The Institute of Cancer Research, Clinical Trials and Statistics Unit, London, United Kingdom, 3The Institute of Cancer Research, London, United Kingdom, 4Mount Vernon Cancer Centre, Northwood, United Kingdom, 5The James Cook University Hospital, Middlesbrough, United Kingdom, 6University Hospital Birmingham, West Midlands, United Kingdom, 7The Clatterbridge Cancer Centre, Liverpool, United Kingdom, 8St. Bartholomew's Hospital, London, United Kingdom, 9Colchester Hospital University NHS Foundation Trust, Colchester, Essex, United Kingdom, 10Charing Cross Hospital, London, United Kingdom, 11Arden Cancer Centre, Coventry, United Kingdom, 12The Royal Marsden Hospital, London, United Kingdom, 13Radiotherapy Trials Quality Assurance Group, London, United Kingdom, 14Independent Patient and Public Representative, London, United Kingdom, 15The Institute of Cancer Research, Sutton, United Kingdom
Purpose/Objective(s):
Treatment selection for localised prostate cancer (LPCa) is often influenced by expected functional outcomes, assuming comparable cancer control between treatments. Randomised evidence comparing efficacy of radical prostatectomy and stereotactic body radiotherapy (SBRT) is lacking.Materials/Methods:
PACE (NCT01584258) is phase III, open label, multicohort randomised controlled trial. In PACE-A, men with LPCa (cT1-T2, Gleason score =3+4, PSA =20 ng/mL) who were suitable candidates for prostatectomy were randomised (1:1) to SBRT or prostatectomy. SBRT was delivered to 36.25 Gy in 5 fractions over 1-2 weeks. Prostatectomy could be open, laparoscopic, or robot assisted. Androgen deprivation therapy was not permitted. Freedom from biochemical/clinical failure (BCF), based on PSA rises (nadir+2ng/ml or >0.2 ng/ml post radiotherapy or prostatectomy) or commencement of ADT or recurrence or metastases or prostate cancer death was analysed using Cox proportional hazards and log-rank test by intention to treat.Results:
123 patients were randomised from 8 centres between August 2012 and February 2022 (60 prostatectomy, 63 SBRT). Baseline characteristics were well-balanced between groups. Median age was 65.5 years (IQR 60.5-68.6), median pre-treatment PSA was 7.9ng/mL (IQR 5.9-11.0), 5.7% and 94.3% of patients had low/intermediate-risk disease, respectively. With median follow-up of 8 years (IQR: 6.1 – 8.0), 13 BCF events had occurred (5 SBRT, 8 prostatectomy), unadjusted hazard ratio 0.48 (95% CI 0:16-1.46; p=0.18). The estimated absolute difference at 5 years (based on the HR) is 3.1% (95% CI -2.6, 5.0) with 5-year BCF-free rates 94.8% (84.6, 98.3) and 94.1% (82.6, 98.1) for SBRT and prostatectomy. 8-year rates were 91.2% (80.1, 96.2) and 83.7% (68.4, 92.0). Subsequent treatment for progression included surgery in 1 SBRT patient and radiotherapy in 5 prostatectomy patients. ADT was administered to 5 patients (3 prostatectomy, 2 SBRT). At 5 years, using Expanded Prostate Cancer Index Composite 26-item (EPIC-26) questionnaire, use of =1 urinary pad was reported by 3/36(8.3%) SBRT patients and 14/29(48%) prostatectomy patients. 1/28(3.6%) prostatectomy patient and 0 SBRT patients reported moderate/big bowel function problem. Clinician reported CTCAE grade =2 gastrointestinal side effects were reported by 1/54(2%) patient receiving SBRT and 0 prostatectomy patients. Grade =2 genitourinary side effects occurred in 2/53 (3.8%) receiving SBRT and1/40 (2.5%) patients undergoing prostatectomy.Conclusion: With long-term follow-up, both prostatectomy and SBRT achieved excellent biochemical control in patients with localised prostate cancer. These findings support SBRT as an effective non-surgical treatment option with comparable long-term disease control to prostatectomy.