ESTRO 2022 - Abstract Book

S78

Abstract book

ESTRO 2022

3-4 serious adverse reactions during CRT were reported as follows: 5/45 (11.1%) in SD arms, 4/46 (8.7%) in HD arms, 5/38 (13.2%) in CRT+N arms and 4/38 (10.5%) in CRT-only arms. 1-year local progression (with/without metastasis) and local- only (no metastasis) progression rate was 33.3% and 26.7% (SD arms) and 23.9% and 15.2% (HD arms) respectively. Overall resection rate (11%) and quality of life were similar for all arms. Conclusion The addition of nelfinavir and/or RT dose escalation to 60Gy failed to improve outcomes in LAPC. RT dose escalation to 60Gy was well tolerated.

OC-0104 Stereotactic radiation for treatment of oligometastases (SABR-COMET) – Extended long-term outcomes

D. Palma 1 , R. Olson 2 , S. Harrow 3 , S. Gaede 4 , A.V. Louie 5 , C. Haasbeek 6 , L. Mulroy 7 , M. Lock 1 , G.B. Rodrigues 1 , B.P. Yaremko 1 , D. Schellenberg 8 , B. Ahmad 1 , S. Senthi 9 , A. Swaminath 10 , N. Kopek 11 , M. Liu 12 , R. Schlijper 2 , G.S. Bauman 1 , J. Laba 1 , X.M. Qu 1 , A. Warner 1 , S. Senan 6 1 London Health Sciences Centre, Radiation Oncology, London, Canada; 2 British Columbia Cancer Agency, Radiation Oncology, Prince George, Canada; 3 Edinburgh Cancer Centre, Clinical Oncology, Edinburgh, United Kingdom; 4 London Health Sciences Centre, Oncology, Medical Biophysics, Physics and Engineering, London, Canada; 5 Sunnybrook Health Sciences Centre, Radiation Oncology, Toronto, Canada; 6 Amsterdam University Medical Center, Radiation Oncology, Amsterdam, The Netherlands; 7 Nova Scotia Cancer Centre, Radiation Oncology, Halifax, Canada; 8 British Columbia Cancer Agency, Radiation Oncology, Surrey, Canada; 9 Alfred Health Radiation Oncology, Radiation Oncology, Melbourne, Australia; 10 Juravinski Cancer Centre, Radiation Oncology, Hamilton, Canada; 11 McGill University Health Centre, Radiation Oncology, Montreal, Canada; 12 British Columbia Cancer Agency, Radiation Oncology, Vancouver, Canada Purpose or Objective There is a lack of long-term randomized data assessing the impact of ablative therapies in patients with oligometastases. The SABR-COMET randomized phase II trial was originally designed with 5 years of follow-up, but in light of better-than- expected survival outcomes, the trial was amended in 2016 to extend follow-up to 10 years. Herein we report oncologic outcomes beyond 5 years. Materials and Methods We enrolled patients with a controlled primary tumour and up to five metastatic lesions, with all sites of disease amenable to stereotactic ablative radiotherapy (SABR). Patients were randomized in a 1:2 ratio between palliative standard of care (SOC) treatment (control arm) vs. SABR to all metastases plus SOC (SABR arm). The primary endpoint was overall survival (OS) and secondary endpoints included progression-free survival (PFS), toxicity, quality of life (QOL, using the FACT-G), and time to new metastases. This analysis took place in January 2022, after 5 years of minimum potential follow-up in all patients. Results Ninety-nine patients were randomized between 2012-2016 (n=33 in Arm 1 vs. n=66 in Arm 2). Primary tumour sites included lung (n=18), breast (n=18), colon (n=18), prostate (n=16), and other (n=29). Median age was 68 years and most were male (60%). Eight-year OS was 27.2% in the SABR arm vs. 13.6% in the control arm (HR: 0.50, 95% CI: 0.30-0.84; stratified log- rank p=0.008). 8-year PFS estimates were 21.3% vs. 0%, respectively (HR: 0.45, 95% CI: 0.28-0.72; p < 0.001). Rates of grade ≥ 2 acute or late toxicities were 30.3 vs. 9.1% respectively (p=0.019), most commonly fatigue and pain, with no new grade 3-5 toxicities. There was no difference between arms in the cumulative incidence of new metastases (stratified Gray’s p=0.46). FACT-G QOL scores declined over time in both arms, but there were no differences in QOL scores between arms. The use of systemic therapy overall was similar between arms, but patients in the SABR arm were less likely to require cytotoxic chemotherapy (33% vs. 55% respectively, p=0.043). Of the 25 patients in the SABR arm alive beyond 5 years, 11 had no progression events since SABR, and 5 others required salvage SABR at some point after randomization. Conclusion SABR achieved durable improvements in OS and PFS, with no new major toxicity signals with extended follow-up. A minority of patients randomized to the SABR arm (1-in-6) achieved > 5 years of survival without recurrence. Ongoing imaging follow- up after SABR is warranted to detect salvageable recurrences. D. Dearnaley 1 , V. Hinder 2 , A. Hijab 3 , G. Horan 4 , N. Srihari 5 , P. Rich 6 , G. Houston 7 , A. Henry 8 , S. Gibbs 9 , R. Venkitaraman 10 , C. Cruickshank 11 , S. Hassan 2 , M. Mason 12 , I. Pedley 13 , H. Payne 14 , S. Brock 15 , R. Wade 16 , A. Robinson 17 , O. Din 18 , K. Lees 19 , J. Murray 20 , C. Parker 21 , C. Griffin 22 , A. Sohaib (Senior Author) 23 , E. Hall (Senior Author) 24 1 The Institute of Cancer Resarch and Royal Marsden NHS Foundation Trust , Division of Radiotherapy and Imaging, London, United Kingdom; 2 The Institute of Cancer Research, Clinical Trials and Statistics Unit, London, United Kingdom; 3 The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Division of Radiotherapy and Imaging, London, United Kingdom; 4 The Queen Elizabeth Hospital King's Lynn NHS Foundation Trust UK, Clinical Oncology, King's Lynn,, United Kingdom; 5 The Shrewsbury and Telford Hospital NHS Trust, Clinical Oncology, Shrewsbury , United Kingdom; 6 St George’s University Hospitals NHS Foundation Trust, Radiology, London, United Kingdom; 7 University of Dundee and Tayside Health, Imaging Science and Technology,, Dundee, United Kingdom; 8 University of Leeds, Clinical Oncology, Leeds, United Kingdom; 9 Barking, Havering and Redbridge University Hospitals NHS Trust,, Clinical Oncology, London, United OC-0105 PROMPTS RCT of screening MRI for spinal cord compression in prostate cancer (ISRCTN74112318)