Ovarian Yolk Sac Tumors; Does Age Matter?

Background: Whereas among pediatric oncologists, ovarian yolk sac tumor (O-YST) is considered a chemosensitive tumor, it is often cited as an adverse prognostic factor in adult women with ovarian germ cell tumors.
Methods: The Malignant Germ Cell International Consortium data set included 6 pediatric clinical trials (United States, United Kingdom, and France) and 2 adult gynecology clinical trials (United States). Any patient with an O-YST that was International Federation of Gynecology and Obstetrics stage IC or higher and treated with a platinum-based chemotherapy was eligible. Age was modeled as a continuous and a categorical variable (children, 0-10 years; adolescents, 11-17 years; and adults, ≥18 years). In addition, analyses to establish the optimal cut point for age were conducted. Tumors were coded as pure YST (YST +/- teratoma), mixed YST (YST + other malignant germ cell component), or putative YST ("mixed" germ cell tumor + alpha-fetoprotein >1000 ng/mL). Histology, stage (II/III vs IV), preoperative alpha-fetoprotein levels (<1000; 1000-10,000, or >10,000 ng/mL), and chemotherapeutic regimen (carboplatin vs cisplatin) were analyzed as covariates.
Results: Two hundred fifty-one patients (median age, 13 years; range, 0-38 years) were identified (78 children, 139 adolescents, and 34 adults). Histology was pure, mixed, and putative in 129, 56, and 66 cases, respectively. Twenty-six patients had stage IV disease, similarly distributed in the 3 age groups. Median follow-up was 5.8 years. The overall 5-year event-free survival and overall survival was 91% (95% confidence interval, 87%-94%) and 96% (92%-98%), respectively. Age did not affect risk of event or death, modeled either as a categorical or continuous variable. Analysis failed to identify an age cut point that affected risk. None of the other covariates investigated had a prognostic impact on event-free survival or overall survival.
Conclusions: Ovarian yolk sac tumors have an excellent outcome across all age-groups. Age has no apparent impact on the probability of event or death, allowing pediatric and gynecologic oncologists to enroll patients onto joint pediatric and adult trials.