title: Patterns of Failure Following Multimodal Treatment for Medulloblastoma: Long-Term Follow-up Results at a Single Institution.
abstract: OBJECTIVE
  The purpose of this study is to investigate the long-term results and appropriateness of radiation therapy (RT) for medulloblastoma (MB) at a single institution.
  
  
  METHODS
  We analyzed the clinical outcomes of 106 patients with MB who received RT between January 1992 and October 2009. The median age was 7 years (range, 0 to 50 years), and the proportion of M0, M1, M2, and M3 stages was 60.4%, 8.5%, 4.7%, and 22.6%, respectively. The median total craniospinal irradiation (CSI) and posterior fossa tumor bed dose in 102 patients (96.2%) treated with CSI was 36 Gy and 54 Gy, respectively.
  
  
  RESULTS
  The median follow-up period in survivors was 132 months (range, 31 to 248 months). A gradual improvement in survival outcomes was observed, with 5-year overall survival rates of 61.5% in 1990s increasing to 73.6% in 2000s. A total of 29 recurrences (27.4%) developed at the following sites: five (17.2%) in the tumor bed; five (17.2%) in the posterior fossa other than the tumor bed; nine (31%) in the supratentorium; and six (20.7%) in the spinal subarachnoid space only. The four remaining patients showed multiple site recurrences. Among 12 supratentorial recurrences, five cases recurred in the subfrontal areas. Although the frequency of posterior fossa/tumor bed recurrences was significantly high among patients treated with subtotal resection, other site (other intracranial/spinal) recurrences were more common among patients treated with gross tumor removal (p=0.016). There was no case of spinal subarachnoid space relapse from desmoplastic/extensive nodular histological subtypes.
  
  
  CONCLUSIONS
  Long-term follow-up results and patterns of failure confirmed the importance of optimal RT dose and field arrangement. More tailored multimodal strategies and proper CSI technique may be the cornerstones for improving treatment outcomes in MB patients.
authors: Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System, Seoul, Korea.
authors: Dong Soo
authors: DS
authors: Lee
authors: Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System, Seoul, Korea.
authors: Jaeho
authors: J
authors: Cho
authors: Department of Pathology, Severance Hospital, Yonsei University Health System, Seoul, Korea.
authors: Se Hoon
authors: SH
authors: Kim
authors: Department of Neurosurgery, Severance Hospital, Yonsei University Health System, Seoul, Korea.
authors: Dong-Seok
authors: DS
authors: Kim
authors: Department of Neurosurgery, Severance Hospital, Yonsei University Health System, Seoul, Korea.
authors: Kyu Won
authors: KW
authors: Shim
authors: Department of Pediatrics, Severance Hospital, Yonsei University Health System, Seoul, Korea.
authors: Chuhl Joo
authors: CJ
authors: Lyu
authors: Department of Pediatrics, Severance Hospital, Yonsei University Health System, Seoul, Korea.
authors: Jung Woo
authors: JW
authors: Han
authors: Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System, Seoul, Korea.
authors: Chang-Ok
authors: CO
authors: Suh
mesh_terms: D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D016543:Central Nervous System Neoplasms / Q000628:therapy*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008527:Medulloblastoma / Q000628:therapy*; D008875:Middle Aged; D011829:Radiation Dosage; D011878:Radiotherapy; D012008:Recurrence; D012189:Retrospective Studies; D055815:Young Adult
keywords: Craniospinal irradiation; Medulloblastoma; Radiotherapy; Recurrence
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