P01.116 Treatment with Dabrafenib in a patient with BRAF mutated recurrent ganglioglioma

Abstract BackGround Gangliogliomas are rare tumor usually arising in the supratentorial region, WHO grade 1 or 2. In these tumors, BRAF mutation may constitute a driver genetic alteration and a biomarker of response to BRAF inhibitors. Dabrafenib is an oral inhibitor of BRAF and has shown to significantly improve progression-free survival in patients with BRAF mutated metastatic melanoma. Materials and Methods In March 2015, after being diagnosed with left front-temporal enhancing mass, a 31-year-old lady was referred to the University Hospital of Pisa. In the previous two months, the patient had noticed motor aphasia and, due to the persistence of the symptoms, she was sent to the emergency room by the general practitioner. Previous history did not show any co-morbidity. An MRI displayed a fronto-parietal tumor with some contrast enhancement. The patient underwent craniotomy and subtotal tumor resection. Histopathology revealed a WHO grade I ganglioglioma and immunohistochemistry (IHC) documented focal expression of P-53, CD34, and ki-67 proliferation index of 3%. BRAF V600E mutation (Val600Glu(GTG◊GAG)) was detected by polymerase chain reaction. Postoperatively, the patient received radio-chemotherapy with temozolomide (60 Gy in 30 fractions), but 10 months later the patient experienced disease progression. A second surgery was performed without any neurological impairment. The disease monitoring with MRI revealed a partial tumor removal and the pathology confirmed the previous diagnosis. After second surgery, considering the Karnofsky Performance Status Score of 100, the young age and, the presence of BRAF mutation, our multidisciplinary team (in agreement with colleagues of the Neuro-Oncology Unit of the University of Turin) decided to administer the selective BRAF inhibitor Dabrafenib (75 mg twice per day for the first 21 days, then 150 mg twice per day). Since the beginning of the salvage systemic therapy, the patient did not experience treatment-related adverse events. Magnetic resonance performed two months after the start of Dabrafenib and then every three months showed a major response. After 15 months due to the persistent disease response and MRI, we decided to stop the administration of Dabrafenib. Three months after interruption of dabrafenib a new MRI detected a second disease progression being the patient asymptomatic, and we decided to restart the administration of Dabrafenib, which is ongoing. Conclusion Despite the lack of literature on