ESTRO 2023 - Abstract Book

S629

Monday 15 May 2023

ESTRO 2023

Conclusion This is the first randomised controlled trial comparing SBRT to 3D-CRT for pain relief in both spine and non-spine bone metastases where patients remained blinded to their treatment arm. SBRT was safe and did not result in any excess toxicity. Dose-escalation improved complete pain response rate 1 month after radiotherapy, although less than anticipated and not statistically significant. However, for patients with an expected survival of at least 3 months, there might be a clinically relevant benefit. OC-0763 SAbR in LA-NSCLC patients unfit for concurrent ChT-RT: START-NEW-ERA non-randomised phase II trial F. Arcidiacono 1 , P. Anselmo 1 , M. Casale 1 , C. Zannori 2 , F. Loreti 3 , M. Ragusa 4 , B. Enrico 5 , F. Mancioli 5 , G. Marchetti 6 , M. Italiani 1 , S. Fabiani 1 , A. Guida 7 , V. Tassi 4 , C. Caprera 8 , M. Corsi 8 , S. Bracarda 9 , E. Maranzano 10 , F. Trippa 10 1 Radiotherapy Oncology Centre "S.Maria" Hospital, Oncology, Terni, Italy; 2 Medical Oncolgy "S.Maria" Hospital, Oncology, Terni, Italy; 3 Nuclear Medicine Service "S.Maria" Hospital, Oncology, Terni, Italy; 4 Thoracic Surgery Division "S.Maria" Hospital, Oncology, Terni, Italy; 5 Radiology Service "S.Maria" Hospital, Oncology, Terni, Italy; 6 Pathology Unit "S.Maria" Hospital, Oncology, Terni, Italy; 7 Medical Oncology "S.Maria" Hospital, Oncology, Terni, Italy; 8 Pathology Unit “S. Maria” Hospital, Oncology, Terni, Italy; 9 Medical Oncology “S. Maria” Hospital, Oncology, Terni, Italy; 10 Radiotherapy Oncology Centre “S. Maria” Hospital, Oncology, Terni, Italy Purpose or Objective This is an update of a single arm phase 2 trial (Clinical trials.gov NCT05291780) to assess local control (LC) and safety of stereotactic ablative radiotherapy (SAbR) in newly diagnosed and recurrent unresectable locally advanced non-small cell lung cancer (LA-NSCLC) patients unfit for concurrent chemo-radiotherapy (ChT-RT). Early results on first 50 enrolled patients were recently published (1). Materials and Methods Patients were staged with PET-CT and brain MRI. Neoadjuvant ChT was prescribed in fit patients. The tumor volume included primary tumor (T) and any regionally positive node/s (N). The co-primary study endpoints were LC and safety. Results Between December 31, 2015 and June 30, 2022 71 LA-NSCLC patients were enrolled. All analyses, including the primary end-points of LC and safety, included patients with at least 6 months of follow-up after treatment with clinical and imaging tumor response evaluation. Histology was squamous cell carcinoma (SCC) and adenocarcinoma (ADC) in 41% and 59%, respectively. 61 (86%) patients had ultra-central tumor. Forty (56%) received neoadjuvant ChT and 15 (21%) adjuvant Durvalumab. Median prescribed dose was 45 Gy (range, 35-55) and 40 Gy (35-45) in 5 daily fractions to T and N, respectively. After a median follow-up of 26 months (range, 6-92), 23 (32%) patients had experienced local recurrence (LR). The median LR-free survival (FS) was not reached (95% CI, 28 to not reached). The 1-, 2- and 4- year LR-FS rates were 84±5%, 67±6% and 58±7%, respectively. At last follow-up, 46 (65%) patients were alive. Median overall survival (OS) was 55 months (95% CI, 43-55 months). The 1, 2, and 4-year OS rates were 92±3%, 72±6% and 58±7%, respectively. Twenty-two (31%) patients developed distant progression (dP). The median dP-FS was not reached (95% CI, 24 to not reached). The 1, 2, and 4-year dP-FS rates were 85±4%, 64±6% and 60±7%, respectively. Two patients developed grade (G) 3 esophageal and lung toxicity Conclusion LA-NSCLC patients treated with SAbR had optimal LC and promising OS with low rate of G3 toxicity. Our updated clinical outcomes confirm the feasibility of using this approach in LA-NSCLC patients unfit for concurrent ChT-RT. 1. Int J Radiat Oncol Biol Phys 2022;S0360-3016(22)03459-9. doi: 10.1016/j.ijrobp.2022.10.025 OC-0764 The rate and spatial location of local recurrences: Results from the EORTC 22922/10925 O. Kaidar-Person 1 , P. Giasafaki 2 , L. Boersma 3 , P. De Brouwer 4 , C. Weltens 5 , C. Kirkove 6 , K. Peignaux-Casasnovas 7 , V. Budach 8 , F. van der Leij 9 , E. Vonk 10 , N. Weidner 11 , S. Rivera 12 , G. van Tienhoven 13 , A. Fourquet 14 , G. Noel 15 , M. Valli 16 , M. Guckenberger 17 , E. Koiter 18 , S. Racadot 19 , R. Abdah-Bortnyak 20 , H. Bartelink 21 , H. Struikmans 22 , C. Fortpied 2 , P. Poortmans 23 1 Sheba Medical Center, Breast Radiation Unit, Ramat Gan, Israel; 2 EORTC , Headquarters, Brussels, Belgium; 3 GROW-School for Oncology and Reproduction, Maastricht University Medical Centre, Dept. Radiation Oncologv (Maastro), Maastricht , The Netherlands; 4 Institute Verbeeten, Department of Radiation Oncology, Tilburg, The Netherlands; 5 University Hospital Leuven, Department of Radiation Oncology,, Leuven, Belgium; 6 University Hospital Saint Luc, Université Catholique de Louvain, Department of Radiation Oncology, Brussels, Belgium; 7 Centre Georges François Leclerc, Department of Radiation Proffered Papers: Breast