High Dose Gefitinib for the Treatment of Carcinomatous Meningitis in Adult Patients With Non-Small Cell Lung Cancer and Known or Suspected EGFR Mutations

On days 1-14 gefitinib will be taken orally daily at either 750, 1000, or 1250mg (depends upon when subject entered trial). If medication is tolerated well, subject will take 500mg daily on days 15-28 of each 28-day cycle. Cycles (higher dose followed by lower dose) will be repeated as long as subject's cancer does not worsen and they do not experience any serious side effects.