Clinical Characteristics of Cohort
Fifty-four patients diagnosed between 1997 and 2013 met our inclusion criteria; the clinical characteristics of the cohort are listed inTable 1 . Seventy-four percent of patients in our cohort (40/54) had M0 disease. Two of the 54 patients (4%) received chemotherapy prior to RT: 1 of these patients was 2 years old at diagnosis and received chemotherapy treatment according to the Children’s Oncology Group ACNS0334 for patients with high risk infant medulloblastoma until he reached the age of 3 years at which time CSI was initiated, and the 2nd patient received 2 cycles of topotecan prior to starting RT.
All patients initiated RT within 35 days of tumor resection. Patients with standard-risk medulloblastoma received 23.4 Gray (Gy) CSI, while those with high-risk disease received 36-39.6 Gy CSI; both populations then received a boost to the tumor bed to a total dose of 54-55.8 Gy. Eighty percent of patients (43/54) received proton beam RT, while the remaining 11 patients received photon beam RT. For patients that were treated with proton therapy, the entire vertebral body was covered with the CSI prescription dose for skeletally immature patients, while for those who had achieved skeletal maturity, only the posterior portion of the vertebral body was treated during CSI.
One patient (2%) received concurrent chemotherapy during RT; however, the chemotherapy was single agent vincristine, which is not myelosuppressive. Following completion of RT, 82% of patients (44/54) received chemotherapy either enrolled on or treated according to clinical trials SJMB96 or SJMB03 with vincristine, cisplatin, and cyclophosphamide.