PATIENT CHARACTERISTICS: Age: Over 18 Performance status: ECOG 0-2 Life expectancy: Greater than 3 months Hematopoietic: Hemoglobin greater than 10 g/dL WBC greater than 3,000/mm3 Platelet count greater than 100,000/mm3 Hepatic: Bilirubin less than 1.8 mg/dL AST less than 3 times upper limit of normal (ULN) Alkaline phosphatase less than 3 times ULN No hepatitis B Renal: Creatinine less than 1.4 mg/dL OR Creatinine clearance greater than 50 mL/min Cardiovascular: No New York Heart Association class II cardiac disease Pulmonary: No pulmonary disease requiring oxygen therapy Other: Not pregnant Fertile patients must use effective contraception during study and for 3 months following No concurrent serious nonmalignant disease No AIDS No uncontrolled infection No uncontrolled diabetes No medical condition that will interfere with taking oral temozolomide