MBCL-06. SUCCESSFUL SALVAGE OF DESMOPLASTIC NODULAR MEDULLOBLASTOMA PATIENTS TREATED ON ACNS1221

Abstract Desmoplastic nodular medulloblastoma (DNMB) is among the most treatable pediatric brain tumors with overall survival often reported in the range of 80-90%. Recently, several attempts around the globe were initiated in order to scale back therapy with the hopes of reducing both the short and long term toxicities. Unfortunately, these efforts have not been successful to date, which is highlighted by the most recent early closure of the Children’s Oncology group trial, ACNS1221, due to increased incidence of progression. There is no consensus at this time regarding the best salvage regimen to use for patients who failed therapy on ACNS1221. Here we present two patients with DNMB who recurred after treatment on ACNS 1221 and were successfully salvaged with high dose chemotherapy and stem cell support at our institution. The first patient is a 3 years old male who recurred with metastatic disease within 3 months post-therapy. He was treated with a 5-drug regimen consisting of vincristine, cisplatin, etoposide, cyclophosphamide and high-dose methotrexate for 3 cycles with autologous tandem transplants and proton craniospinal irradiation therapy of 23.4Gy and a boost to the posterior fossa of 54 Gy and the spine to 45 Gy. The second patient is a 4 years old male with Gorlin Syndrome and Trisomy 21 who had local recurrence within 9 months from finishing therapy, and was salvaged with 3 cycles of carboplatin and thiotepa with autologous tandem stem cell support without the need for radiation therapy. Both patients are currently alive with no evidence of disease.