Radiation Oncology/Medulloblastoma/Staging

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Medulloblastoma Staging


Modified Chang's Staging[edit | edit source]

T Stage

  • T1 - tumor <3 cm in diameter
  • T2 - tumor ≥3 cm in diameter
  • T3a - tumor >3 cm and with extension into Aqueduct of Sylvius or foramen of Luschka
  • T3b - tumor >3 cm and with unequivocal extension into brainstem
  • T4 - tumor >3 cm with extension past Aqueduct of Sylvius or down past foramen magnum

M Stage

  • M0 - No evidence of gross subarachnoid or hematogenous metastasis
  • M1 - microscopic tumors cells found in CSF
  • M2 - gross nodular seeding intracranially beyond the primary site (in cerebellar/cerebral subarachnoid space or in third or lateral ventricle)
  • M3 - gross nodular seeding in spinal subarachnoid space
  • M4 - metastasis outside cerebrospinal axis


Risk Stratification[edit | edit source]

  • Standard (Average) Risk (66%)
    • >3 years old
    • <1.5 cm2 residual disease after resection
    • M0 by craniospinal MRI and CSF
  • High Risk (34%)
    • <3 years old
    • Subtotal resection, >1.5 cm2 residual tumor
    • M+; leptomeningeal seeding
    • Location outside of posterior fossa (PNET)