Surgical resection and outcome of malignant ovarian germ cell tumors in children-a national multicentric study compared to international results

Purpose To evaluate the outcome of pediatric malignant ovarian germ cell tumors treated by three tertiary Egyptian institutions, and to compare our national experience to internationally published data. Methods This is a retrospective analysis of all patients presenting between September 2014 and September 2019. Management protocol was Children's Oncology Group (COG) in all participating centers. Overall survival (OS), event-free survival (EFS) and univariate prognostic factors were estimated by Kaplan-Meier and log-rank test. Additionally, a review of various practices that reported survival outcome was conducted. Main results Thirty-seven patients were included with a median age of 10.5 years (1-18 years). Thirty-five patients had unilateral salpingo-oophorectomy. Mixed germ cell and yolk sac tumors represented 75.7% of patients. There were 7 (19%), 14 (37.8%), 12 (32.4%) and 4 (10.8%) stage I, II, III and IV, respectively. Seven patients were low risk (LR), 26 intermediate risk (IR) and 4 high risk (HR). Platinum-based chemotherapy was administered as per risk stratification. Follow-up to March 2020 revealed that five patients had relapsed. There were no statistical significances of pathological types and patients' age regarding OS (pvalue 0.392 and 0.281, respectively) and EFS (pvalue 0.420 and 0.437, respectively). Three-year OS was 84%: 100% for stages I and II, and 62% for stages III and IV (p = 0.003); 100% for LR, 89% for IR, and 24% for HR (p < 0.001). Three-year EFS was 87%: 96% for stages I and II, and 71% for stages III and IV (p = 0.025); 100% for LR, 92% for IR, and 26% for HR (p < 0.001). Conclusion Surgical resection combined with chemotherapy achieves excellent outcome for such tumors in both, present study and previous reports. On the basis of our results, COG staging and risk stratification were significantly correlated with prognosis, whereas tumor pathology and age had no significant impact. Prognostic factors are controversial among studies, and further research is still required.