Among the most promising chemotherapeutic regimens is high-dose methotrexate. Neoadjuvant high-dose methotrexate has been shown to double median survival time for patients with primary CNS lymphoma from 12 to 8 months to more than 40 months. In addition, regimens that incorporate better drugs for bulky disease but also treat the CSF and microscopic disease with intravenous and intrathecal methotrexate have been proposed. Immunocompromised patients with CNS lymphoma generally respond poorly to chemotherapy and tolerate treatment poorly, as well. They often succumb to opportunistic infections.
Treatment involves maximum safe resection, followed by staging.
At diagnosis, medulloblastomas occasionally have metastasized to bone or other extraneural structures, and commonly exhibit leptomeningeal seeding. The implication of CSF contamination is that with the exception of infants, the entire neuraxis is irradiated at diagnosis. Infants and young children are especially vulnerable to toxicities of treatment. Treatment Recommendations Whole-neuraxis radiation alone is recommended for patients greater than 3 years of age with minimal residual tumor after surgery, and without evidence of CSF or systemic dissemination. Chemotherapy plus craniospinal irradiation is recommended for patients with bulky leptomeningeal or disseminated disease, who are know to be at high-risk for recurrence.