Radiation Oncology/Medulloblastoma/Staging

Medulloblastoma Staging

Modified Chang's Staging
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

 * 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)