Embryonal Tumors of the Central Nervous System Treatment & Management

Updated: May 08, 2023
  • Author: Nir Shimony, MD; Chief Editor: Stephen L Nelson, Jr, MD, PhD, FAACPDM, FAAN, FAAP, FANA  more...
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Treatment

Medical Care

Preoperative administration of steroids can help to alleviate some of the signs and symptoms of embryonal tumors of the CNS by reducing peritumoral edema. [2]

Radiation therapy

Radiation therapy, usually given adjuvantly, should be performed under the direction of a radiation oncologist. Many series report a clear, dose-dependent relationship between postoperative radiation and local tumor control. Adjuvant radiotherapy alone, with posterior fossa doses of 5000 cGy and neuraxis doses of 3000 cGy, results in a 5-year event-free survival rate of 50-70%. Lower than standard doses of radiation therapy, at least without chemotherapy, are less effective. Craniospinal axis radiation is used for patients with spinal dissemination.

Newer methods are being evaluated, including stereotactic radiosurgery and high fractionation radiotherapy. [16] These methods limit the radiation dose to the local sites and avoid potential adverse effects in children, including cognitive dysfunction or delay in growth, that is seen frequently with conventional radiotherapy.

Radiation therapy by most protocols is reserved for patients older than 3 years old. It is customary to define if the patient is with average or low risk vs. high risk before the initiaion of treatment. CSI is carefully utilized only for selected cases. According to some protocols, for those that are average risk a dose of 23.4 Gy is given whereas 36–39.6 Gy is given for high risk. In both cases a boost to the primary site (55.8-59.4 Gy) is given. [14]  

Chemotherapy

Chemotherapy should be administered under the direction of a medical oncologist.

Varying combinations of drugs used in these tumors include, but are not limited to, lomustine (CCNU), vincristine, cisplatin, etoposide (VP-16), topotecan, and cyclophosphamide. Several trials, including those from the Pediatric Oncology Group (POG) and Children's Cancer Group (CCG), are underway, evaluating varying combinations of chemotherapy with and without radiotherapy. For children younger than 3 years old "CSI sparing" chemotherapy protocols are being used.

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Surgical Care

Surgery aims to achieve radical tumor resection, when possible, and restore normal CSF outflow.

Like in other cases, since the adjuvant treatment has partial success, when feasible, it is important to start the adjuvant treatment when there is no residual tumor ( whenever it is feasible in a safe manner). Hence, it is advisable to consider second-look surgeries before the initiation of either radiation therapy or chemotherapy. [17]  Recent publication of the Rare Brain Tumor Registry study showed benefit for acheiving GTR. [18]

Permanent CSF diversion in the form of ventriculoperitoneal shunt or endoscopic 3rd ventriculostomy (ETV) is required in as many as 30% of these cases.

Current treatment modalities include surgery, chemotherapy, and/or radiation. Ongoing worldwide research has explored nonconventional therapeutic strategies such as immunotherapy and gene therapy to improve outcomes and survival, although their clinical efficacy is yet to be established. [19]  Current publications shows mixed results regarding benefit of GTR, brainstem involvement, metatatic disease, and radiation therapy. [14, 18]

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Consultations

Consultation with the following may prove helpful:

  • Neurosurgeon

  • Neurologist/pediatric neurologist

  • Radiation oncologist

  • Medical oncologist

These cases are complex and pose complex treatment and diagnosis questions. Hence, it is advisble these cases will be discussed as part of experience center that practice multidisciplinary approach for the treatment of these patients. 

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