Histologic determinants of long-term overall survival in patients (pts) with germ cell tumors (GCT).

Abstract

4555 Background: GCT display totipotential differentiation ranging from pluripotent embryonal carcinoma to extraembryonic (choriocarcinoma, yolk sac) to somatic cell types (teratoma [T]). We hypothesized that long-term survival after platinum-based chemotherapy (PC) is dependent upon histology. Methods: Advanced GCT pts who received PC from 4/1975 to 5/1996 and had a pre-PC primary tumor specimen available were included. Each pre-PC cell type was reviewed and confirmed. Residual tumor size post-PC was recorded when available. Differences in cumulative incidence (CUI) of death due to disease (DOD) between histologic cell types and other baseline characteristics were evaluated using a competing risks approach and the Fine & Gray test. Results: Pre-PC primary tumor specimens (96% testis, 3% mediastinum) were available from 231 pts. Median age was 29 years (y) and median followup 17 y (range 0.3-35 y). 41 pts had pure seminoma; of the remaining 190 with nonseminomatous GCT (NSGCT), 81 had an element of T (n=29 mature T, n=42 immature T, n=10 both). At PC start, 60% of pts were IGCCCG good risk, 26% intermediate, and 13% poor with no difference for NSGCT based on presence vs. absence of T (p=0.53). Of 72 deaths, 50 were DOD, 20 from other causes, and 2 from unknown causes. The 5, 10, and 15 y CUI of death from any cause was 20%, 23%, and 26%, respectively. CUI of DOD at 5, 10 and 15 y was 18%, 20%, 22%, respectively. CUI of DOD at 2, 5, 10 and 15 y by histologic group is provided in the Table. Presence of T was associated with greater CUI of DOD vs. NSGCT without T (p=0.04) and mature T with a greater CUI of DOD vs. immature T (p=0.03). NSGCT pts with T were also more likely to have residual retroperitoneal disease >1cm after PC vs. those without T (50 vs. 4.2%; p=0.01). Conclusions: With long-term followup, the presence of an element of T, particularly mature T, in mixed NSGCT was associated with a higher risk of DOD than tumors without T, which have the same risk of DOD as pure seminoma. These data suggest that the presence of T in the primary tumor may be an important clinical predictor of long-term outcome in men with GCT. [Table: see text]