Study of Temozolomide to Treat Newly Diagnosed Brain Metastases

Inclusion Criteria: Tumor characteristics adequate for stereotactic radiosurgery: 1. 1-3 newly diagnosed, previously untreated, brain metastases 2. Each tumor measuring a size less than or equal to 3 cm 3. No other contraindications to stereotactic radiosurgery Systemic parameters adequate for temozolomide following stereotactic radiosurgery: 1. Histological confirmation of systemic malignancy (brain confirmation not required) 2. Male or female 18 years of age or older 3. Negative pregnancy test (if of childbearing potential) 4. Any number of previous recurrences will be allowed 5. Karnofsky Performance Status \> 60 6. Hematocrit \> 30,000 7. White blood cell count \> 1,500 8. Platelet \> 100,000 9. Absolute Neutrophil Count \> 1,000 10. Bilirubin \< 1.5 x upper limits of normal 11. Transaminases (ALT and AST) \< 1.5 x upper limits of normal 12. Creatinine \< 1.5 x upper limits of normal 13. Adequate medical health to participate in this study 14. Adequate documentation of menopause (natural/surgical) or patient commitment to routine use of reliable birth control (barrier/hormonal) 15. Ability to read and understand the informed consent document 16. Ability and willingness to follow all requirements of the study including following all directions, taking medication as prescribed and completing all diaries and forms 17. No other contraindications to temozolomide (severe organ dysfunction, immunosuppression, etc.) 18. Medical stability and/or recovery from effects of stereotactic radiosurgery Exclusion Criteria: 1. Karnofsky Performance Status \< 60 2. Hematocrit \< 30,000 3. White blood cell count \< 1,500 4. Platelet \< 100,000 5. Absolute Neutrophil Count \< 1,000 6. Bilirubin \>1.5 x upper limits of normal 7. Transaminases (ALT and AST) \> 1.5 x upper limits of normal 8. Creatinine \> 1.5 x upper limits of normal 9. Inability to undergo gadolinium-contrasted MRIs, including severe claustrophobia or insufficient allergy prophylaxis 10. Germ cell, leukemia, and lymphoma histologies will be excluded 11. Prior chemotherapy or radiotherapy for brain metastases (prior resection and steroids are allowed) 12. Contraindications to radiosurgery or temozolomide chemotherapy 13. Uncontrolled systemic malignancy 14. Chemotherapy or other systemic therapy for systemic malignancy within a specified time of temozolomide initiation, depending on half-life of agent: 1. Cytotoxic chemotherapy within the previous 4 weeks 2. Nitrosurea (CCNU, BCNU) within the previous 6 weeks 3. Gliadel or temozolomide within the previous 4 weeks 4. Bevacizumab or other antiangiogenic agent within the previous 4 weeks 5. Other targeted molecular or antibody agent within the previous 4 weeks 6. Hormonal agent within the previous 2 weeks