GCT-02. THE LONG-TERM OUTCOMES AND SEQUELAE ANALYSIS OF INTRACRANIAL GERMINOMA FROM 187 PATIENTS IN THE SINGLE INSTITUTE: NECESSITY FOR THE ADAPTATION OF RADIOTHERAPY DOSE AND VOLUME

PURPOSE: We aimed to refine the radiotherapy (RT) volume and dose determinant for disease failures and long-term sequelae in the intracranial germinoma. METHODS: The main treatment for intracranial germinoma was craniospinal RT only (n=51) during 1981–1992 and RT with upfront chemotherapy (CRT) (n=152) during 1992–2015 in Seoul National University Hospital. All 187 cases were confirmed histologically. RT fields included craniospinal, whole-ventricle (WV), whole-brain (WB), and focal radiotherapy. RT dose was dependent on the M status and combination of chemotherapy. The median follow-up duration was 115 months (range, 3–358). RESULTS: The 10-year overall and recurrence-free survival was 94.5% and 91.4%. The complete response rate after chemotherapy was 62.6%. For the patients with complete response, WV RT 16–20 Gy, and focal boost of 25–36 Gy after upfront chemotherapy showed no in-field recurrence. The causes of death were progression (n=3), 2(nd) malignancy (n=6), treatment-related complications (n=7), and others (n=8). For non-sellar tumors, the rate of hormonal replacement treatment was significantly related to WB RT and WB/WV RT dose ≥ 30 Gy (p=.030, and .026). After a latency of the median 20 years, ten patients (5.3%) developed 2(nd) malignancy. WB RT and WB/WV dose ≥ 30 Gy were significantly correlated with the 2(nd) malignancy (p=.024, and .004). The rate of severe neurocognitive dysfunction was significantly associated with WB/WV dose ≥ 30 Gy (p=.027). CONCLUSION: CONCLUSION: RT with or without upfront chemotherapy exhibits the excellent control rate of disease. However, the intensity and volume of RT are critical for managing treatment toxicities. Adaptation and further de-intensification of RT should be followed.