RARE-46. MULTIMODAL TREATMENT OF TWO PATIENTS WITH DISSEMINATED JUVENILE PILOCYTIC ASTROCYTOMA

Juvenile Pilocytic Astrocytoma (JPA) is characterized by an indolent course with excellent survival if gross total resection is achieved. However, a rare subset of these low-grade neoplasms will disseminate. We present two patients with disseminated JPA and review the multimodal treatment approach required to manage this disease. CLINICAL IMPORTANCE: Disseminated JPA is a low-grade tumor with a chronic relapsing course. Radiation has previously been successful, however, the significant treatment volume needed for disease control is toxic in young children. Approaches using repeated surgical resections and multiple chemotherapy regiments to postpone time to radiation is becoming a standard approach. CLINICAL OUTCOME: Our first patient is a 7-year-old girl who had four progressions in her primary third ventricular mass in the last 2 years. Her disseminated disease has been stable throughout treatment. Initially, she underwent subtotal resection of third ventricular mass, which showed JPA, with negative BRAF v600e and negative BRAF fusion. After observation, she had her first progression and was treated with vincristine and carboplatin. Three months later she had her second progression and then treated with six cycles of selumetinib. Next, she received weekly vinblastine prior to her fourth progression. She then underwent gross total resection of her primary mass and has disease stability for five months. Our second patient is a 13-year-old male who had two progressions in last seven years. After initial subtotal resection, he had local progression and had a second resection of cerebellar mass. After four years of stability, the mass disseminated to his thoracolumbar spine. He underwent resection of spinal tumor which showed positive BRAF fusion and then treated with carboplatin and vincristine. He is showing mild response to treatment after 6 months of chemotherapy. CONCLUSION: We demonstrate that with using multimodal treatment with surgery and chemotherapy regiments, radiation for young children can be postponed.