GCT-64. TREATMENT RESULTS IN CHILDREN WITH LOCALIZED CNS NGGCT

BACKGROUND/OBJECTIVES: Treatment of children with CNS NGGCT remains challenge: 5y OS is 60 – 80%; relapses are very aggressive. DESIGN/METHODS: Between 2003 and 2019, 14 children (median age 10.5, range 4 – 16 years) with localized intracranial NGGCT were treated with RT after induction chemotherapy (focal – 4, WVI+boost – 6, WBI+boost – 3, CSI+boost – 1). Tumor markers were elevated in 13 patients: 6 – AFP, 5 – HCG, 2 – both. One patient with level of HCG 72049 IU/l in serum and 121451 IU/l in CSF received 4 cycles of PEI + CSI 30 Gy with boost 54Gy. RESULTS: At a median follow-up of 4,7 years (range 1 – 16,25 years), 12 patients are alive. 5-year PFS and OS are 77,1% and 85,7%, respectively. Two patients (both AFP and HCG) progressed during RT (1 – focal, 1 – WBI+boost), both died. Two patients with high level of HCG recurred after therapy (WVI+boost – 1, focal – 1), both are alive. The first of them at recurrence (mts of lateral ventricle) received 4 cycles of PEI and RT (WBI+boost). The second patient had level of HCG 620IU/l and initially received focal irradiation 54Gy. At recurrence with distant spinal mts he received HD-CHT with auto-SCT, surgical resection of residual tumor and CSI with boost. CONCLUSIONS: Good results of treatment of localized CNS NGGCT with CSI, WBI or WVI in compare with focal RT show advantages of extended irradiation field. CSI should be considered for patients with extremely high levels of tumor markers and respectively poor prognostic histology.