PTCT-03: RELAPSE MEDULLOBLASTOMA IN INFANT: COMPLETE RESPONSE WITH TEMOZOLOMIDE AND IRINOTECAN

Infants with relapse medulloblastoma (MB) usually have a dismal prognosis with an overall survival of less than 25%. Currently, there is no standard therapy established for recurrent MB. The combination of temozolomide and irinotecan has been investigated with variable results with a response rate approaching 30%. We report a 30 months old infant with prolonged and drastic response to this chemotherapy combination. This young infant presented at 9 months old with a two weeks history of bulging fontanelle and VI nerve palsy. Brain MRI showed a fourth ventricular mass with hydrocephalus. There was no evidence of metastatic dissemination. She underwent a complete resection. Pathology was compatible with a non-WNT, non-SHH classic MB. Cerebrospinal fluid was negative. Due to her age, she initially received two cycles of chemotherapy including cisplatin, cyclophosphamide, vincristine and high-dose of IV methotrexate. Unfortunately, she progressed locally and received local radiotherapy to 54 Gy. MRI conducted after radiotherapy showed a complete response of the targeted lesion but new leptomeningeal lumbar dissemination. She then received temozolomide (150 mg/m2 PO for 5 days) with irinotecan (50 mg/m2 IV for 5 days) for 12 cycles. She had a complete radiographic response and chemotherapy was withheld. However, on surveillance MRI two months later, she was found to have recurrent leptomeningeal disease involving lumbar spine. Temozolomide and irinotecan was restarted and a significant radiographic response was observed. We achieved a complete radiographic response in an infant with relapse MB whereas her tumor was resistant to conventional chemotherapy. Subtypes of medulloblastoma appear to respond drastically to temozolomide and irinotecan and this regimen offers an interesting option. However, the addition of other treatments modalities is essential to achieve a prolonged survival. The ongoing Children Oncology Group trial will likely assess the efficacy of this regimen with and without bevacizumab.