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)