Treatment strategies for pediatric extracranial germ cell tumors

Abstract

According to registry data from the Japanese Society of Pediatric Hematology and Oncology, extracranial germ cell tumors (GCTs) represent approximately 13% of all solid tumors in patients under 20 years of age, with nearly half classified as mature teratomas. Approximately 140 new cases are diagnosed annually in Japan. Age distribution showed a biphasic pattern, with the first peak in infancy (0–4 years), and the second peak appearing after 9 years in girls and after 11 years in boys. Data from previous clinical trials conducted by the Malignant Germ Cell International Consortium identified age >11 years, COG stage IV disease, and an extragonadal origin as adverse prognostic factors. Surgical resection remains the cornerstone of treatment, while systemic chemotherapy is incorporated in cases that are unresectable or considered high-risk. Pediatric chemotherapy regimens were initially developed based on adult GCT protocols; however, pediatric outcomes are generally superior. Concerns about bleomycin-related toxicity in infants have led to the adoption of the PEb regimen (reduced-dose bleomycin) as the standard of care. Carboplatin-based JEB regimens have been used to mitigate cisplatin-induced nephrotoxicity and ototoxicity. Evidence regarding salvage or relapsed pediatric GCTs remains limited, emphasizing the need for further investigations. Future progress will require not only international collaborative studies but also cross-disciplinary development involving both pediatric and adult oncology.