Is there some predictive factors for isolated brain PROgression in patients with CErebral metastatic MElanoma after stereotactic brain radiotherapy ? PROCEME

Abstract Melanoma is a skin cancer with an excellent prognosis if diagnosed at an early stage. However, it has a high potential for brain metastasis, making the prognosis considerably poorer. In current practice, we observe discordant responses and progression at cerebral and extra-cerebral levels. The aim of this study was to identify predictive factors of isolated brain progression after treatment with stereotactic brain radiotherapy, with or without systemic treatment. Between January 2014 and December 2020, 121 patients treated by stereotactic brain radiotherapy (Cyber Knife) were included. Radiotherapy was associated to systemic treatment in the major of cases (Targeted Therapies, Immunotherapy, or Chemotherapy). In our cohort, 83 patients showed progression after stereotactic brain radiotherapy: 38 in brain only, 45 in brain and at distance. The study showed a double increase in the risk of isolated brain progression in BRAF V600 mutated patients compared with BRAF V600 WT patients. BRAF V600 mutated melanomas seems more at risk of isolated brain escape in our cohort, we therefore need to develop new local therapies for these patients in the future, and clarify the mechanisms of intrinsic and extrinsic resistance.