Prognostic factors in children with extragonadal malignant germ cell tumors: a pediatric intergroup study

To investigate prognostic factors for pediatric extragonadal malignant germ cell tumors (PEMGCT).

Between 1990 and 1996, patients with stage I through IV PEMGCT were eligible for a trial of cisplatin dose intensity. We retrospectively investigated prognostic factors for PEMGCT, including age, stage, primary site, treatment, and elevated alfa fetoprotein by univariate and multivariate analysis.

The 165 patients had a median age of 1.9 years (range, 3 days to 18.5 years); 109 were female; and 99 had alfa fetoprotein > or = 10,000. There were 30 stage I/II, 61 stage III, and 74 stage IV tumors; primary sites included 88 sacrococcygeal, 39 thoracic, and 38 others. The 5-year overall survival (OS) and event-free survival (EFS) rates with standard deviations were 83.4% +/- 3.7% and 79.0% +/- 4.1%, respectively. Univariate analysis identified age > or = 12 years as a highly significant prognostic factor for EFS (5-year EFS, 48.9% +/- 15.6% v 84.1% +/- 3.9%; P < .0001) and for OS (5-year OS, 53.7% +/- 14.9% v 88.5% +/- 3.4%; P < .0001), whereas treatment was of borderline significance (P = .0777). Multivariate Cox proportional hazards regression identified only age > or = 12 years as a significant prognostic factor for EFS (P = .0002). In multivariate Cox regression for OS, the combination of age and primary site was highly significant (P < .0001). Patients > or = 12 years of age with thoracic tumors had six times the risk of death compared with patients younger than 12 years with other primaries.

Age is the most predictive factor of EFS in PEMGCT. There is a significant interaction between age and primary site, suggesting that patients > or = 12 years of age with thoracic tumors are a biologically distinct group.