While Xeloda can help treat brain cancer it also sometimes causes non cancerous brain diseases as reported in anecdotic cases by PUBMED.
When Xeloda does not help other treatments are available, among them Temodar already mentioned .
Also worth mentioning is this experimental treatment successfully tried in Germany on a single patient who failed to lastingly respond to various drug regimens : Herceptin injected in the spine to reach the brain in spite of the blood brain barrier which prevents intravenous Herceptin to cross it.
http://patient.cancerconsultants.com/news.aspx?id=36779