Temozolomide With or Without Radiation Therapy to the Brain in Treating Patients With Stage IV Melanoma That Is Metastatic to the Brain

DISEASE CHARACTERISTICS: Histologically confirmed unresectable metastatic melanoma Must have asymptomatic brain metastasis that is not amenable to surgery or stereotactic radiosurgery (gamma knife, Linac) Must have concurrent visceral/soft tissue metastases At least 1 site of measurable disease (not necessarily the brain metastasis) Documented evidence of disease progression defined by 1 of the following conditions: More than 25% increase in the size of at least 1 measurable lesion Appearance of a new lesion A significant increase in the size of nonmeasurable disease No neurological symptoms, including signs of elevated intracranial pressure PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hemoglobin at least 10 g/dL Hepatic: Bilirubin less than 1.5 times upper limit of normal (ULN) SGOT or SGPT less than 3 times ULN Alkaline phosphatase less than 3 times ULN Renal: Urea less than 1.5 times ULN Creatinine less than 1.5 times ULN Other: No frequent vomiting or medical condition (e.g., partial bowel obstruction) that would interfere with oral medication intake No other prior or concurrent malignancy except surgically cured carcinoma in situ of the cervix or basal cell or squamous cell skin cancer No uncontrolled infection HIV negative No AIDS-related illness Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No psychological, familial, sociological, or geographical condition that would preclude study PRIOR CONCURRENT THERAPY: Biologic therapy: Prior cytokine via isolated limb perfusion for local-regional melanoma allowed No other prior cytokine for metastatic melanoma No concurrent colony-stimulating factors, including epoetin alfa or filgrastim (G-CSF) No other concurrent immunologic or biologic therapy Chemotherapy: Prior chemotherapy via isolated limb perfusion for local-regional melanoma allowed No other prior chemotherapy for metastatic melanoma No other concurrent chemotherapy Endocrine therapy: Concurrent corticosteroids allowed during radiotherapy (arm II only) No concurrent hormonal therapy Radiotherapy: See Disease Characteristics No other concurrent radiotherapy Surgery: See Disease Characteristics Recovered from the effects of any prior major surgery Other: No other concurrent investigational drugs