[Carcinomatous meningitis: The radiation therapist's point of view].

Carcinomatous meningitis complicates 5 to 10% of cancers, essentially with breast cancers, lung cancers and melanomas. The incidence probably increased because of therapeutic advances in oncology. Treatment is based on external beam radiotherapy, systemic treatment, intrathecal chemotherapy and supportive care. The aim of this work was to review data on external radiation therapy and carcinomatous meningitis. There are few evidences on the subject, but it is a major topic of interest. A whole brain radiation therapy is indicated in case of brain metastases or clinical encephalitis. Focal radiation therapy is recommended on symptomatic, bulky or obstructive sites. The dose depends on performance status (20 to 40 Gy in five to 20 fractions), volume to treat and available techniques (classic fractionation or hypofractionation via stereotactic radiosurgery). The objective of radiation therapy is to improve quality of life. Association with systemic therapy improves overall survival. Administration of sequential intrathecal chemotherapy may also improve overall survival, but induces more toxicity. The use of new radiotherapy techniques and development of radiosensitizing molecules in patients with good performance status could improve survival in this frequent complication of cancer.