Temozolomide in Treating Patients With Metastatic Germ Cell Tumors That Have Not Responded to Cisplatin

DISEASE CHARACTERISTICS: Histologically confirmed metastatic germ cell tumor Seminoma OR Nonseminoma Measurable disease Abnormalities on radiograph OR Alpha fetoprotein greater than 15 ng/mL OR Beta human chorionic gonadotropin greater than 2.2 mIU/L At least one measurable disease site that has not received prior radiotherapy Refractory to prior cisplatin and failed, not eligible for, or refused autologous bone marrow transplantation PATIENT CHARACTERISTICS: Age: 16 and over Performance status: Karnofsky 70-100% Life expectancy: At least 3 months Hematopoietic: WBC at least 3,000/mm3 Absolute neutrophil count at least 1,000/mm3 Platelet count at lest 80,000/mm3 Hemoglobin at least 10 g/dL Hepatic: Bilirubin no greater than 1.5 times normal Transaminases no greater than 1.5 times upper limit or normal (ULN) Alkaline phosphatase no greater than 3.0 times ULN Renal: Creatinine no greater than 1.5 times ULN Other: No medical conditions that would interfere with swallowing or cause excessive vomiting No second malignancy except basal and squamous cell skin cancer Not pregnant or nursing Negative pregnancy test Fertile patients must use effective barrier contraception PRIOR CONCURRENT THERAPY: Biologic therapy: See Disease Characteristics Chemotherapy: See Disease Characteristics Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics Surgery: Not specified