title: The clinical experience of medulloblastoma treatment and the significance of time sequence for development of leptomeningeal metastasis.
abstract: OBJECTIVE
  Among patients with medulloblastoma, an unrare aggressive central nervous system (CNS) tumor found mostly in the posterior fossa, drop metastasis from primary location to anatomically lower sites including whole spinal cord is known as a potential way for tumor to spread. There were already lots of extensive discussions regarding diagnosis and treatment for such common neurologic complication in systemic cancer; however, fewer were found about medulloblastoma. This study aimed to reexamine the possible known prognostic factors, especially drop metastasis, and defined the influence of them.
  
  
  METHODS
  We retrospectively review a series of 36 patients who suffered from posterior fossa medulloblastoma and found leptomeningeal metastasis in 12 of them. Incidence, diagnosis, prognostic factors, and treatments for this common complication are discussed. The magnetic resonance images (MRI) of these patients were reviewed. The time sequence between primary surgical procedure and development of MRI evidences of drop metastasis was used for subgrouping. Log-rank test was used for survival analysis.
  
  
  CONCLUSIONS
  By survival analysis, patients with late drop metastasis, defined as new radiologic evidence of leptomeningeal involvement after primary CNS procedures, were found to have significant survival difference to those with early metastasis defined as drop metastasis found at the time of diagnosis (log-rank test, p = 0.0047). Further stratification of patients within this group may help in evaluation of prognosis and development of different treatment strategies.
authors.affiliation: Department of Neurosurgery, Chang Gung Memorial Hospital, No. 5, Fu-Shin Street, Kwei-Shan, Taoyuan, 333, Taiwan, Republic of China. PoChuan.Hsieh@gmail.com
authors.forename: Po-Chuan
authors.initials: PC
authors.lastname: Hsieh
authors.forename: Chieh-Tsai
authors.initials: CT
authors.lastname: Wu
authors.forename: Kuang-Lin
authors.initials: KL
authors.lastname: Lin
authors.forename: Tang-Her
authors.initials: TH
authors.lastname: Jaing
authors.forename: Chen-Kan
authors.initials: CK
authors.lastname: Tseng
authors.forename: Tai-Ngar
authors.initials: TN
authors.lastname: Lui
authors.forename: Shih-Ming
authors.initials: SM
authors.lastname: Jung
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015192:Infratentorial Neoplasms / Q000473:pathology* / Q000628:therapy; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008527:Medulloblastoma / Q000473:pathology* / Q000628:therapy; D008577:Meningeal Neoplasms / Q000175:diagnosis / Q000556:secondary* / Q000628:therapy; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors; D055815:Young Adult