Medication Summary
Historically, the most active drugs have been DNA alkylators. These agents cause DNA damage and disrupt DNA replication. Most chemotherapy is given in the inpatient setting. Standard of care regimens in North America incorporate the below chemotherapeutic agents:
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Vincristine
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Lomustine
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Cisplatin
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Cyclophosphamide
Infant protocols generally incorporate the addition of the following chemotherapeutic agents:
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Etoposide
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Methotrexate (high dose)
Different high dose chemotherapy regimens have been used previously. In North America, the most commonly used regimens are either a single transplant with carboplatin, thiotepa and etoposide OR triple tandem transplantation with smaller doses of carboplatin and thiotepa. The currently open Head Start IV multi-institutional trial seeks to address the use of a single versus triple tandem regimen.
Antineoplastic agents
Vincristine (Vincasar PFS)
Vincristine, a plant-derived vinca alkaloid used during radiotherapy and in combination with other chemotherapeutic agents. Acts as a mitotic inhibitor by binding tubulin. Common adverse effects include peripheral motor and sensorineural neurotoxicity and constipation. This agent by itself does not cause myelosuppression or nausea/vomiting.
Lomustine (Gleostine)
Lomustine (CCNU), a nitrogen mustard and DNA alkylator used in combination with other chemotherapeutic agents. Acts by crosslinking DNA resulting in damage to the DNA templation and inhibits DNA replication. Common adverse effects include myelosuppression as well as GI toxicity.
Cisplatin
Cisplatin, a heavy metal platinum derivative used in combination with other chemotherapeutic agents. It exerts its cytotoxic effect by platination of DNA. Acts similarly to alkylating agents by crosslinking DNA and inhibiting DNA replication. Common adverse effects include myelosuppression, acute and delayed onset nausea and vomiting, hair loss, ototoxicity and nephrotoxicity and electrolyte disturbance (e.g. hypomagnesemia).
Cyclophosphamide
Cyclophosphamide, a phosphoramide mustard and DNA alkylator used in combination with other chemotherapeutic agents. Common adverse effects include myelosuppression, nausea/vomiting, hair loss, and hemorrhagic cystitis.
Methotrexate (Xatmep, Trexall, Rasuvo, Otrexup)
Methotrexate, a folate antimetabolite, is given at high doses to facilitate CSF penetration. Common adverse effects include nausea/vomiting, myelosuppression, mucositis, and nephrotoxicity.
Etoposide (Toposar)
Etoposide (VP-16), a semisynthetic plant derivative of podophyllotoxin. It is a topoisomerase II enzyme inhibitor and forms a ternary complex with DNA causing DNA strands to break. Common adverse effects include infusion reactions, low blood pressure, hair loss, metallic taste, and myelosuppression.
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MRI showing a medulloblastoma of the cerebellum.
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Section displaying Homer-Wright rosettes and pseudorosettes of a medulloblastoma.
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This section displays a typical medulloblastoma, composed of undifferentiated cells with deeply basophilic nuclei of variable size and shape and little discernible cytoplasm.
Tables
Tumor Stage |
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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 |
Metastases Stage |
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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 |
