NIRA-06 MELANOMA BRAIN METASTASES AND ASSOCIATED INTRACEREBRAL BLEEDS: THE ROLE OF WHOLE-BRAIN RADIATION THERAPY

Abstract OBJECTIVE It is well recognized that melanoma has a predilection for brain involvement; however, its propensity of causing an intracerebral hemorrhage (ICH) has yet to be determined. The purpose of this current study was to describe the natural history of metastatic melanoma-associated ICH, and to evaluate its occurrence in the setting of prior whole-brain radiation therapy (WBRT) and stereotactic radiosurgery (SRS). PATIENTS AND METHODS Following institutional review board approval, a retrospective chart review was performed, including all patients with malignant melanoma treated at our institution, who suffered a secondary, tumor-associated brain hemorrhage. RESULTS 1,120 patients with brain metastases secondary to melanoma were identified, and of those, 182 (16.3 %) were diagnosed with a tumor-associated brain hemorrhage. Of these 182 patients, 81 (44.5%) underwent testing for the presence of a BRAF mutation. In these patients, neither the type of radiation therapy (X2=3.03, p=0.082) nor BRAF mutation (X2=6.30, p=0.39) related to the development of ICH post radiation. Forty two (51.8%) of these patients experienced a brain bleed after radiation treatment; 31 (73.8%) had a BRAF mutation while 11 (26.2%) did not. BRAF status, mutant versus wild type (p<0.001, 95% CI 0.34-0.47), and the use of a BRAF inhibitor (p<0.001, CI 0.49-0.62) were both significantly associated with the time between radiation therapy and hemorrhage. Post-treatment ICH developed sooner in BRAF mutant patients (87.81 days versus 99.1 days) and in patients were treated with a BRAF inhibitor (71.92±1.66 days versus 125.00±2.80 days). CONCLUSIONS While the frequency of tumor-associated ICH is likely not impacted by delivery of WBRT, the time between tumor-associated ICH and radiation therapy is associated with BRAF mutation and BRAF inhibitor treatment. Future studies ought to examine how BRAF mutation and other tumor and treatment-related factors contribute to post-treatment ICH.