GC-04: INTENSITY-MODULATED RADIOTHERAPY (IMRT) FOR WHOLE VENTRICLES IN PATIENTS WITH INTRACRANIAL GERM CELL TUMOR

BACKGROUND AND OBJECTIVE: As for the radiotherapy of intracranial germinoma, irradiation area and dose have been able to decrease based on its histological type. The localized germinoma achieves as good outcome as whole-brain and whole-spine radiation when treated by whole-ventricle irradiation with chemotherapy. The aim of this study is to evaluate the outcome of intracranial germinomas treated with whole-ventricle irradiation using Intensity-Modulated Radiation Therapy (IMRT) at Kyoto University Hospital from 2002 to 2014. PATIENTS AND METHODS: 26 patients were diagnosed as intracranial germinoma and treated with radiotherapy and/or chemotherapy at our institution from 2002 to 2014. 16 patients were done whole-ventricle irradiation with IMRT; 7-fields, total 24-30Gy. Patients with high-hCG or remaining tumor performed additional focal irradiation. The treatment plan were compared IMRT with 3DCRT. RESULTS: The mean follow-up period is 62 months. All patients have not experienced any adverse events and relapses. As compared to 3DCRT, IMRT achieved irradiated volume reduction of normal brain tissue and improvement of PTV coverage. CONCLUSIONS: IMRT improves target dose delivery and spares organs at risk, and it is presumed to reduce late adverse effects without impairing local control rate. Because 81% of intracranial germinomas appear at the time of childhood and adolescence, it is important to use effective and safety irradiation technique, but it is necessary to make a plan delivering adequate dose for high risk area such as basal ganglia.