Clinicopathologic Characteristics and Survival of Patients with Rare Malignant Ovarian Yolk Sac Tumors: A Population-based Analysis.

Yolk sac tumors (YSTs) are rare malignant germ cell tumors that usually affect young females. To date, there have been few studies on YSTs. We evaluated the relationship between clinicopathologic characteristics of patients with ovarian YSTs and disease outcome based on Surveillance, Epidemiology, and End Results data. The Kaplan-Meier method and log-rank test were used to evaluate differences in survival rates. Data for 269 patients were analyzed. The incidence of YSTs among ovarian germ cell tumors (OGCTs) cases was 0.4%; median patient age was 22.0 years, and most tumors were unilateral. Patients presented with distant metastasis (37.5%), localized disease (49.1%), and regional spread (8.9%). American Joint Committee on Cancer stage was available for 13 patients (stage IA, n=2; stage IC, n=1; stage IIIA, n=1; stage IIIB, n=3; stage IIIC, n=2; and stage IV, n=4). Survival rates at 1, 3, and 5 years were 91.0%, 84.0%, and 83.2%, respectively, for overall survival (OS) and 92.0%, 85.4%, and 84.5%, respectively, for disease-specific survival (DSS). The 5-year OS and DSS of patients with ovary tumors were 91.5% and 92.9%, respectively, compared to 74.8% and 77.2%, respectively, for those with extra-ovarian spread (P<.001 for both OS and DSS). Age >50 years was associated with shorter OS and DSS (both P<0.001), whereas no associatios of OS and DSS were observed with pathologic grade (P=0.49 for OS and 0.52 for DSS). In summary, YSTs are typically unilateral, of a high grade, and localized to the ovary; extra-ovarian spread has a poor outcome, and postmenopausal women have worse prognosis than premenopausal women.