A phase II trial of proton radiotherapy for medulloblastoma: Preliminary results.

Abstract

CRA9507 Background: Pediatric medulloblastoma (MB) is commonly cured with surgery, chemotherapy and radiation. However, the late effects of radiotherapy can be disabling. Proton radiotherapy irradiates less normal tissue, which should result in fewer late side effects of treatment. The purpose of this study was to describe the clinical outcomes of proton radiotherapy. Methods: All patients had surgery of the primary tumor followed by proton radiotherapy with or without concurrent chemotherapy and adjuvant platinum based chemotherapy. CSI doses ranged from 18-36 GyE, median dose 23.4 GyE. The tumor bed or posterior fossa was brought to 54 GyE. Concurrent enrollment in COG or other protocols was allowed. All pathology and imaging was reviewed at MGH to confirm the diagnosis. Results: 60 patients with MB were prospectively enrolled from May 2003 to December 2009 and 59 were evaluable for this analysis. Median age 6.6 yrs, range 3.5 - 22 years; M/F ratio 1.3; standard risk (SR, 45) or high risk (HR, 14). The median follow-up is 16 months. Two-year overall survival (OS) and progression-free survival (PFS) for the entire group is 91% and 87%. Two-year OS for SR MB and HR MB is 92% and 87%. 54 pts have baseline (BL) neurocognitive testing and 19 pts (14 SR, 5 HR) have follow-up (FU) evaluations including FSIQ spanning at an average of 2 years. Mean FSIQ at BL and FU are 107 and 102 (paired t-test: 0.046). Endocrine late effects include 4 patients with growth hormone deficiency, 1 patient with central hypothyroidism and 2 other endocrinopathies. Audiology information will be presented. Conclusions: Early results of this prospective trial are promising for improving clinical outcomes in patients with medulloblastoma. [Table: see text]