Standard and novel radiotherapeutic approaches to neoplastic meningitis.

Neoplastic meningitis usually occurs late in the natural history of cancer. Adequate staging and assessment of the patient's overall reserves and prognosis are crucial in determining whether aggressive treatment is justified. Although radiotherapy remains the single most effective treatment, it is considered palliative for epithelial cancers and is generally directed to sites of bulky disease that obstruct the flow of cerebrospinal fluid or cause neurologic dysfunction. Such diseases as leukemia, medulloblastoma, and germinoma are exceptions that can be treated definitively with craniospinal irradiation. Innovations in conformal therapy may help to reduce the significant amount of myelosuppression associated with spinal irradiation. The main long-term toxicity associated with whole-brain irradiation (WBI) is dementia resulting from leukoencephalopathy, which may be exacerbated when WBI is given in combination with chemotherapy. A case report highlighting the use of radiotherapy for palliation in a patient with neoplastic meningitis is presented at the end of this article.