Brain metastases are the most common adult intracranial tumor, occurring in approximately 10% to 30% of adult cancer patients, and represent an important cause of morbidity and mortality. The most widely used treatment for patients with multiple brain metastases is whole brain radiation therapy (WBRT). The use of WBRT after resection or stereotactic radiosurgery (SRS) has been proven to be effective in terms of improving local control of brain metastases.