GCT-27. CLINICAL FEATURES AND PROGNOSTIC FACTORS OF NONGERMINOMATOUS GERM CELL TUMORS IN 111 CONSECUTIVE PATIENTS IN A SINGLE INSTITUTION: IMPACT OF IRRADIATION AND CHEMOTHERAPY CYCLES ON SURVIVAL

BACKGROUND: Limited data is available in intracranial nongerminomatous germ cell tumors (NGGCTs) in Chinese population. Here we aimed to retrospectively assess the clinical-pathological and prognostic factors of NGGCTs in a single large institution in China. METHODS: From June 2003 to December 2018, 111 consecutive NGGCTs were treated in Guangdong Sanjiu Brain Hospital, China. RESULTS: The median follow-up was 36.2 months (range, 1.2 to 131.2 months). Three-year EFS and OS for 111 NGGCTs patients were 78.5%±4.5% and 82.8%±4.0%, respectively. 98 patients received CSI plus boost yielded better survival than those who received reduced-volume radiotherapy or no radiotherapy (3y OS, 86.7% vs. 51.4%, p=0.007). Patients had at least four cycles of chemotherapy were strongly associated with improved 3-year OS, compared to those received less than 4 cycles (94.1% vs. 63.6%, p＜0.001). There was no significant difference in survival of patients stratified by age, surgery, hydrocephalus, as well as tumor diameter. Multivariate analysis identified chemotherapy cycles less than 4 was the only prognostic factor that conferring a worse OS (p=0.003). Patients both received CSI and at least 4 courses of chemotherapy were correlated with lower incidence of relapse (p=0.044). CONCLUSIONS: Multimodal approach including CSI and enough courses of chemotherapy was effective and should be recommended for the treatment of newly diagnosed NGGCTs in Chinese population.