Identification of Predictive Factors for Isolated Brain Progression in Patients With Cerebral Metastatic Melanoma After Treatment With Stereotactic Brain Radiotherapy

ABSTRACT Background Melanomas often metastasize to the brain, leading to a significantly poor prognosis despite advances in local and systemic treatments. In clinical practice, we frequently observe varying response patterns and progression dynamics between cerebral and extra cerebral sites. Objectives This study aims to identify predictive factors for progression of isolated brain metastases after treatment with stereotactic brain radiotherapy, with or without systemic treatment. Methods Between January 2014 and December 2020, 121 patients with stage IV melanoma treated with stereotactic brain radiotherapy were included. Radiotherapy was associated to systemic treatment. Results We reported data of 83 patients with progressive disease after stereotactic brain radiotherapy: 38 intracerebral Progression Disease (PD) and 45 intra and extra cerebral PD. Age appeared to be an independent predictive factor for isolated cerebral progression, with age higher than 75 years associated with higher rate of isolated cerebral progression (OR = 6.01[1.35‐36.2], p = 0.029). Although significant in univariate analysis, BRAF V600 mutation was not statistically associated with a higher incidence of isolated cerebral progression after adjustment on age, gender, number and size of the largest metastasis, treatment during radiotherapy, and number of affected organs. Conclusions In our study, age was the only independent risk factor associated with isolated brain progression.