GCT-20. Presentation and Outcome of Bifocal Germinoma Treated According to Siop CNS GCT Ii

Abstract BACKGROUND Between 2/2012 and 7/2018, 261 patients with germinoma were registered as intent-to-treat patients within the SIOP CNS GCT II trial. 209 patients were male/ 52 female. The median age was 14.1 years (range 5,0-41,0 years). 194 patients had localised and 67 had metastatic disease. 64 patients had bifocal germinoma, defined as synchronous suprasellar and pineal tumours at diagnosis. PATIENTS/METHODS The main symptoms were diabetes insipidus (DI) (n=47), visual impairment (33), raised intracranial pressure (21), headache (20), neurological symptoms (14), non-DI endocrine disturbances (14), and somnolence (12). Diagnosis was confirmed by biopsy in 38/64 patients and by resection in 4/64. 22/64 were diagnosed by imaging only. Patients with localised disease received 24 Gy whole-ventricular irradiation (WVI) alone if they achieved complete response (CR) after induction chemotherapy, or WVI with boost to both tumour sites (16 Gy) if partial response (PR) or stable disease (SD) was documented. Patients with metastases (dissemination on MRI or positive CSF cytology) received cranio-spinal irradiation (CSI) 24 Gy with boost to primary sites/ to visible metastases (16 Gy). RESULTS After induction chemotherapy, 17/40 with localised disease achieved CR, 21/40 PR, and 2/40 SD. After completion of treatment, 16/17 patients who achieved CR after chemotherapy remained in CR and one patient died after a relapse. 13/21 patients with PR post-chemotherapy achieved CR post-treatment, 3/21 remained in PR and 5/21 relapsed, one of which achieved a second CR. Both patients with SD remained in CR after radiotherapy and additional surgical intervention. Among patients with dissemination 21/24 achieved CR and 3/24 PR after completion of treatment (CSI). No relapses occurred. CONCLUSION Localised bifocal germinoma can be treated with WVI ± tumour boost depending on the response to chemotherapy. Bifocal germinoma with or without dissemination have an excellent prognosis. For the SIOP CNS GCT group, supported in part by German Childhood Cancer Aid