[Radiation therapy for brain tumors]

Brain tumors respond differently to treatment with surgery plus radiotherapy or radiotherapy alone, combined with or without chemotherapy, because they are characterized by subtypes with different histologies. Since the development of diagnostic radiology, such as computed tomography (CT) and magnetic resonance imaging (MRI), brain tumors have been easier to demonstrate and can be found at earlier stages than in the conventional situation. Furthermore, highly technical devices and equipment for radiation therapy have been developed and installed for clinical use, especially with multileaf collimator (MLC) and treatment planning systems. In the field of radiotherapy for brain tumors, it has been possible to use more precise treatment planning with conformal radiotherapy, three-dimensional treatment planning, and stereotactic radiotherapy. Dose escalation studies and the modified fractionation schedule of radiotherapy can also be designed by analyzing biological data and applying hypofractionated intensity-modulated radiotherapy (IMRT) to radioresistant tumors such as glioblastoma multiforme and anaplastic astrocytoma. Future investigation may be useful to determine which fraction size is likely to be optimal for these malignant gliomas when highly conformal radiotherapy is used in adjuvant treatment. These technological developments and newly designed radiosensitizing agents will improve local control rates and survival times, thereby enhancing the quality of life in patients suffering from various kinds of brain tumors.