XII. Radiotherapy for CNS GCTs

1. "Diagnostic radiotherapy" or radiation test At the time when open surgeries for pineal and hypothalamic­ neurohypophyseal tumors showed high morbidity and mortality, irradiation was often used to determine the radiosensitivity of the tumor without histological confirmation. However, there is no longer any justification for the use of "diagnostic radiotherapy" or "radiation tests" in order to inspect the histologic nature of pineal and neurohypophyseal lesions. Radiotherapy should not be given before attempting to verify a tumor histology. Although the number of papers which stress the importance of histological diagnosis by surgery has been increasing, until recently the actual percentage of pathological verification before irradiation has been unsatisfactory in Japan [6]. Radiation oncologists should, therefore, en­ courage neurosurgeons to perform diagnostic or resection surgery for pineal and neurohypophyseal tumors. The reason for this recommendation will be described below.