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.