Safety and Tolerability of Low-Dose Temozolomide During Whole Brain Radiation in Patients With Cerebral Metastases From Non-Small-Cell Lung Cancer (Study P04071)(TERMINATED)

Inclusion Criteria: * Prior histologic confirmation of non-small cell lung cancer (NSCLC). * Optional: NSCLC histologic confirmation of metastasis of NSCLC. * Presence of unidimensionally measurable disease in the brain. * No previous or current malignancies at other sites with the exception of adequately treated in situ carcinoma of the cervix or basal and squamous carcinoma of the skin. * Age: \>18 years. * Subjects must not have systemic disease that in the opinion of the investigator is in immediate need of chemotherapy * Karnofsky Performance status \>=70%. * Absolute neutrophil count (ANC) \>1,500/mm\^3, platelets \>100,000/mm\^3, hemoglobin \>8 g/dL. * Serum creatinine and bilirubin \<1.5 times upper normal limit of testing laboratory. * Serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT) \<3 times upper limit of testing laboratory. * Palliative radiation therapy to thorax and bone or other organs (except brain) is acceptable. * Prior neurosurgery \>2 weeks from initiating treatment with temozolomide. * Cortisone medication stable or decreasing within 2 weeks prior to initiating treatment with temozolomide. * Patient is not pregnant or nursing and is advised and willing to use an effective method of contraception. * Written informed consent. Exclusion Criteria: * Chemotherapy or biologic therapy within four weeks prior to initiating therapy with temozolomide. * Prior radiation therapy for brain \<4 weeks from initiating therapy with temozolomide. * Surgery within two weeks prior to temozolomide administration. * Recursive Partitioning Analysis (RPA) class III * Patients with a single brain metastasis amenable to radiosurgery of resection * Known Human Immunodeficiency Virus (HIV) disease. * Acute infection requiring intravenous antibiotics. * Any reason making compliance to the protocol improbable.