Management with Chemotherapy of Tumors in the Nervous System of Children

Initial Management

• Secure route for administration: A central line insertion is usually required for administration of intravenous chemotherapy in children. The intensity of therapy will determine the type of central line. Oral chemotherapy (e.g., temozolomide, lomustine) requires that the patient be able to swallow. If this is not possible, a nasogastric or G-tube will be required.
• Hydration: High volumes of fluids are required with the administration of cisplatin and cyclophosphamide to minimize toxicity. Hydration can be challenging in the setting of patients with diabetes insipidus and may require the assistance of an endocrinologist.
• Level of care: With high-intensity regimens, for example, Head Start, patients should be inpatients or close to a tertiary care hospital for the majority of the chemotherapy induction and consolidation period due to the high risk (up to 10%) of toxic death related to fulminant infection. The author’s experience is that this high toxicity can be minimized with close monitoring, use of RSV prophylaxis (palivizumab) in children under 2 years of age, and rapid initiation of empiric antibiotic +/- antifungal therapy for fever and neutropenia. Pneumocystis prophylaxis is also required. G-csf is required for high-intensity regimens to assist in neutrophil recovery.
• Review of current medications: Certain medications should be avoided with some chemotherapy. The use of other drugs that are ototoxic should be avoided when patients are receiving cisplatin or high-dose carboplatin. CP450 inducers such as phenytoin, which trigger the metabolism of certain chemotherapeutic agents (e.g., etoposide and vincristine) and inhibitors such as valproic acid, which increase the toxicity of these agents, should be avoided if a suitable alternative is available. Dexamethasone should be avoided unless required for raised ICP due to potential interference with chemotherapy infiltration into the tumor.
• Ensure adequate nutrition: The monitoring of nutrition is important as many patients lose weight and require supplemental nutrition via tube feeding during chemotherapy. Nausea can interfere with nutrition, making antiemetics necessary during chemotherapy. It is important to ensure a good bowel regimen to minimize risk of ileus while on vincristine.

Follow-up

• Frequency of office visits: Visits are monthly initially until the central intravenous line is removed and blood counts have normalized. The frequency then lessens to every 3, 6, or 12 months depending on the tumor type and residual issues.
• Frequency of imaging: The frequency of scanning varies with the type and grade of tumor and the treating institution’s protocols. In general, malignant tumors are followed more frequently (every 3 months initially), while benign tumors are scanned less often (3 months after completion of chemotherapy and then every 6 months initially). MRA should be considered when imaging patients with suprasellar tumors whose treatment has included radiation therapy. 
• Other investigations required: Generally, the child’s CBC is checked at least yearly. Other testing may be required when certain chemotherapeutic agents have been administered in the past. Serum electrolyte and magnesium levels are checked if cisplatin has been given; audiology is also checked when there is a history of cisplatin administration. Pulmonary function testing is performed on patients who have received lomustine, and neuropsychological testing may be indicated to follow children who have received methotrexate or radiation or those who have experienced postoperative mutism.
• Advocate for rehabilitation: A neuropsychology evaluation, active educational intervention/support, proactive physical exercise, and an intensive rehabilitation program may be indicated for a child, especially when he or she has required treatment with methotrexate, radiation, or had postoperative mutism.