Role of post-chemotherapy radiation in the management of children and adolescents with primary advanced malignant mediastinal germ cell tumors.

Objective: Primary malignant mediastinal germ cell tumors (MMGCTs) are rare in children and adolescents and have a poorer prognosis than their gonadal counterparts. We report a single institutional experience of a 10-year period of primary advanced MMGCTs treated with chemotherapy, followed by radiotherapy in those who had residual mass.

Methods: Children and adolescents with primary advanced MMGCTs between 2005 and 2014 were identified from the Cancer Center, Sun Yat-Sen University. Medical records were reviewed for clinicopathological characteristics, treatments, and outcomes.

Results: Twenty-four children and adolescents with either stage III or IV primary advanced MMGCTs met the inclusion criteria. There were 23 males and one female with a median age of 16 (range 10-18). Seven cases were seminomas (29.2%); four (16.7%) yolk sac tumors (YST); three (12.5%) choriocarcinomas; and ten (41.6%) nonteratomatous combined germ cell tumors (CGCTs). All patients were treated with first-line cisplatin-based chemotherapy regimens (PEB: 19, VIP: 5). Thirteen (54.2%) and Twelve (50%) patients received surgery and radiotherapy, respectively. With a median follow-up of 46.2 months (range 9.6-124.8 months), a total of five (20%) patients died of disease progression; the five-year overall survival (OS) and disease-free survival (DFS) rates were 82.3% and 64.9%, respectively.-Seven patients with seminoma GCTs received post-chemotherapy irradiation were alive with sustained CR (5-year OS and DFS, 100%, respectively). Five patients with NSGCTs were administered irradiation and one relapsed 35 months later and died of metastasis (5-year OS, 100%; 5-year DFS 66.7%). Univariate analysis identified histology and stage were prognostic factors.

Conclusion: Multimodality treatment approach of chemotherapy followed by radiation consolidation ensured long-term survival in primary advanced MMGCTs. Further research is warranted to improve the prognosis of children with primary advanced MMGCTs.