Is there an increased risk of spinal relapse in standard-risk medulloblastoma/primitive neuroectodermal tumor patients who receive only a reduced dose of craniospinal radiotherapy?

PURPOSE: Medulloblastoma (MBL) is the most common pediatric brain malignancy. Postoperative radiotherapy to the entire craniospinal axis is the standard-of-care but has linked to long-term morbidity. In this study, we analyzed the implication of reduced dose craniospinal radiotherapy (RT) for survival and pattern of relapse in MBL patients. MATERIAL AND METHODS: The clinical characteristics of 32 consecutively diagnosed medulloblastoma/primitive neuroectodermal tumor patients were analyzed. After surgical resection, a dose of 23.4 Gy of spinal RT with a posterior fossa boost of 30.6 Gy was prescribed to standard-risk patients, whereas high-risk patients received 36 Gy spinal RT with additional boosts to the posterior fossa up to 54 Gy. Then, both groups received the same chemotherapy protocol. RESULTS: Five-year OS for standard and high-risk patients was 94 and 50%, respectively. When analyzing prognostic factors, postoperative tumor size is the most important one which affects the OS. Ten patients relapsed during follow-up, and there was no isolated spinal relapse in either group. CONCLUSION: The risk of isolated spinal relapse does not increase with reduced-dose craniospinal RT, since there is no isolated relapse in either the standard or high-risk groups of patients.