ESTRO 2020 Abstract book

S693 ESTRO 2020

are properly met and patient care and referral practice is improved. PO-1226 Safety and outcomes of concurrent immunotherapy and radiation therapy for melanoma brain metastases A. Desagneaux 1 , M.T. Leccia 2 , I. Gabelle Flandin 1 , A.-.M. Dols 3 , A. Kastler 4 , J. Charles 2 , C. Verry 1 1 CHU Grenoble Alpes, Radiotherapy, La Tronche, France ; 2 CHU Grenoble Alpes, Dermatology, La Tronche, France ; 3 CHU Grenoble Alpes, Statistics, La Tronche, France ; 4 CHU Grenoble Alpes, Neuro Radiology, La Tronche, France Purpose or Objective In spite of the promising results of Immune Checkpoint Inhibitor (ICI), the development of brain metastases remains a common issue with almost systematic use of brain RT. Combined ICI and brain RT are a growing issue in the current practice. To assess the safety and outcomes of concurrent ICI and brain RT with a focus on sequencing and timing of both treatments for patients with brain This retrospective and single- institution study included all consecutive patients treated for a brain metastatic melanoma with an ICI (anti – CTLA4 or anti – PD1) and brain RT from December 1, 2010 and April 30, 2018. The concurrent group was defined by an ICI performed within 4 weeks before or after RT. Primary endpoint was neurological adverse events graded with Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Secondary endpoints were Overall Survival (OS), Distant Brain Failure (DBF) and Local Control (LC). Lesions were assessed according to the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) [22] by MRI repeated every 3 months. Results Fifty - three consecutive patients were included. A total of 81 RT sessions were performed: 58 with Stereotactic RT (87.3% with multiple fractions) and 23 with WBRT. The majority of RT (63%, n=51) was delivered with concurrent ICI. Acute Neurological Adverse Events (AE) ≥ grade 3 occurred for 12.3% of RT session, with no difference between concurrent and non – concurrent groups. In univariate analysis, Karnofsky Performance Status score was significantly associated with ≥ grade 3 AE (p=0.018). Among SRT sessions, AE ≥ grade 3 have been recorded for 5.9% for concurrent sessions and 12.5% for non – concurrent sessions. With a median follow-up of 11.4 months, the median OS after RT was 11.5 months for the entire cohort with no difference by looking at timing. Patients treated with SRT compared to WBRT as first radiation had a median OS of 15.9 months in comparison to 2.7 months, respectively (p =0.057). OS was influenced by melanoma- mol GPA score (p=0.03). Regarding brain metastases treated by stereotactic RT (n=88), the median LC was 14.1 months with significant difference, in favor of concurrent SRT and ICI (p =0.007). One-year LC probability was higher in the concurrent group than in the non-concurrent group, respectively 72.4 % vs 38.5%. metastases melanoma. Material and Methods

Conclusion Concurrent RT and IT seems to be well tolerated with acceptable neurological adverse events. Stereotactic Radiation Therapy delivered concurrently with ICI may be associated with improved local control. However, these results need to be confirmed by prospective studies. PO-1227 A dose escalation phase 1 study of radiotherapy combined with ipilimumab in metastatic melanoma. C. Boutros 1 , N. Chaput 2 , E. Lanoy 3 , A. Larive 3 , C. Mateus 4 , E. Routier 4 , S. Roy 4 , R. Sun 5 , A. Lancia 6 , Y.G. Tao 5 , N. Ibrahim 7 , R. Khoury-Abboud 7 , C. Massard 8 , R. Bahleda 8 , D. Schwob 3 , C. Caramella 9 , L. Cassard 10 , J. Soria 11 , C. Robert 12 , E. Deutsch 13 1 Gustave Roussy Cancer Campus, Dermatology Unit- Outpatient Clinic- Department Of Medicine, Villejuif,