Induction Chemotherapy Reduces Radiation Therapy Dose and Volume in the Treatment of Intracranial Germinoma: Results of the SMC-G13 Trial

Abstract

Purpose: We performed a prospective single-arm trial (NCT02782754) to explore the feasibility of reducing radiation therapy (RT) dose when induction chemotherapy is combined in the treatment of intracranial germinoma with beta-human chorionic gonadotropin levels <200 mIU/mL.

Methods and materials: All patients aged 3 to 35 years from November 2012 to June 2018 were eligible for this study. Four cycles of induction chemotherapy were given before RT. Carboplatin/etoposide and cyclophosphamide/etoposide regimens were used in alternation every 3 weeks. A dose of 18 Gy of craniospinal RT for metastatic tumors, whole brain RT for basal ganglia tumors, or otherwise whole ventricular RT followed by 12.6 Gy of boost RT to the primary tumor bed was administered after induction chemotherapy. The primary endpoint of this study was progression-free survival.

Results: A total of 41 consecutive patients were enrolled (location: suprasellar in 12, pineal in 12, both suprasellar and pineal in 11, and basal ganglia in 6 patients). Eleven patients had leptomeningeal seeding. Toxicity during chemotherapy was mild, except for bone marrow suppression. Tumor status after induction chemotherapy was complete response in 33 patients and partial response in 8. All but 2 patients completed the scheduled treatment. All patients but 1 remained event free during a median follow-up of 3.4 (range, 0.3-7.0) years from diagnosis. The 1 patient experienced relapse and died of tumor bleeding. Late effects were not significant except for neuroendocrine dysfunction already present at diagnosis. Vertical growth and cognitive function were not significantly disturbed by treatment.

Conclusions: This study showed the feasibility of reducing RT dose/volume with induction chemotherapy in pathologically pure germinoma with elevated beta-human chorionic gonadotropin levels up to 200 mIU/mL.