Role of Radiation Therapy in the Treatment of Brain Metastases

Abstract

Brain metastases are a common cause of disability and death in patients with cancer, but their management remains a major clinical problem. They can, however, be effectively controlled by radiation therapy, possible modalities being external radiotherapy, brachytherapy(implantation), stereotactic radiosurgery(SRS), or a combination of the above modalities. It can be expected that the neurologic status of patients thus treated will remain stable or improve for most of the period during which they survive；using whole brain radiotherapy, the possible palliation index is 75-80%. Despite treatment, however, as many as 1/3 to 2/3 of patients are expected to die from complications related to the progression of brain metastases. With regard to survival, randomized trials involving dose escalation have not yet shown any advantage over the conventional dose；the same palliation index of 75-80% is expected for 40Gy/20 fractions, 30Gy/10 fractions, and 20Gy/5 fractions. It is clear, however, that a smaller daily dose of radiation(the conventional dose is 200cGy/fraction) will reduce the incidence of radiation induced dementia and improve the quality of life in long term survivors. In certain conditions such as solitary brain metastasis without extracranial disease and good performance status(KPS≥70), a more aggressive approach, including surgical resection and stereotactic radiosurgery can be considered.