Prognostic factors in patients with primary mediastinal germ cell tumors, a surgical multicenter retrospective study.

Mediastinal germ cell tumors are a rare heterogeneous entity. This study tries to determine the prognostic factors of these tumors. We designed a retrospective study of 31 patients with primary mediastinal germ cell tumors treated in three centers, in France, from 1986 to 2009. The data were statistically reviewed; univariate and multivariate analyses were performed. Twenty-nine patients were males and two were females (sex ratio 14.5) with a median age of 28 years (range 16-60 years), including: non-seminomatous germ cell tumors 61.3% (n=19), seminoma 32.3% (n=10) and immature teratoma 6.4% (n=2). They had extramediastinal disease at diagnosis in 53% (n=16). The five-year overall survival (OS) was 56.3%. Univariate analysis showed that age, gender, extent of disease at diagnosis, tumor markers at diagnosis and normalization of markers after first-line chemotherapy were not statistically significant, meanwhile tumor histology (P=0.009), surgical resection of the tumor (P=0.023), and pathological evidence of persistent viable tumor in resected remnants (P=0.008) were statistically significant. Multivariate analysis identified surgical resection of the tumor as an independent favorable factor of OS (OR=5.10; 95% CI 1.49-17.45; P=0.009). Determining relevant prognostic factors has been difficult until now, largely because of the low incidence of these tumors. Raising the patient numbers by expanding the centers studied may allow the prognostic factors to be identified more precisely.