Object. The purpose of this study was to identify possible risk factors leading to carcinomatous meningitis in patients with a known brain metastasis and who were treated with gamma knife radiosurgery (GKS).
Methods. Two hundred eighty lesions in 101 patients were treated during 121 GKS procedures. The clinical and neuroimaging history, tumor histology, and follow-up studies were reviewed for all patients. Evidence as demonstrated by magnetic resonance imaging criteria and/or cerebrospinal fluid (CSF) cytology of carcinomatous meningitis was evaluated. The data were then analyzed to identify potential risk factors for the development of CSF dissemination.
Conclusions. It appears that carcinomatous meningitis is exclusively identified in patients with adenocarcinoma, in particular with primary lung cancer. Furthermore, the incidence is higher if surgery is performed and the interval to subsequent GKS is prolonged.