1- Patients with non small cell lung cancer (NSCLC) confirmed by Pathological Anatomy techniques. 2-Patients with one or more measurable brain metastatic lesions who, at the time of inclusion, are not eligible for surgical treatment (total exeresis), defined as those than can be accurately measured in, at least, one dimension (meaning the greater diameter) using imaging techniques (CAT and/or NMR). 3- The study includes metastasis detected during diagnosis and evolving metastasis. 4- Patients could have received any previous onco-specific treatment (surgery, chemotherapy, radiotherapy or any other) for primary lung tumor, provided that such treatment had ended, at least, 4 weeks before being included in the study and who, at the time of inclusion, are only receiving palliative radiotherapy to treat brain metastatic disease. The trial can also include phase IV patients who are only on radiotherapy to treat lung primary tumor and those who are concurrently under radiotherapy for brain metastasis. 5- Patients with brain metastasis diagnosed up to 6 weeks earlier. 6- Reproductive-age patients should have a negative pregnancy test and all patients included in the trial should use effective contraceptive methods. 7- Age >= 18 years. 8- Life expectancy >= 12 weeks. 9- General health condition according to the Karnosfsky Index >= 60. 10- Laboratory parameters within the normal limits, defined as: hematopoietic parameters: haemoglobin>= 9 g/l, total leukocytes >= 4 x 109 cells/l, platelets >= 100 x 109/l, Liver: liver functioning within normal limits and without liver conditions confirmed by TGP, TGO or alkaline phosphatase. Kidney function: serum creatinine<132 mmol/l, creatinine clearing within normal limits. 11- Patients who sign the informed consent document.