Stage IA vs. IB endometrial stromal sarcoma: Does the new staging system predict survival?

Abstract

Objective To determine the correlation of the new FIGO staging system with survival in stage I patients with low-grade and high-grade endometrial stromal sarcomas. Methods Data were extracted from the Surveillance, Epidemiology, and End Results database between 1988 and 2005. Kaplan–Meier log rank and Cox proportional hazards models were used for survival analysis and to identify possible predictors for survival. Results The identified cohort included 464 women, 310 (67%) low-grade endometrial stromal sarcoma, 96 (21%) high-grade endometrial stromal sarcoma, and 58 (12%) unclassified endometrial stromal sarcoma. Among low-grade and high-grade endometrial stromal sarcomas, there was no significant demographic or clinico-pathologic difference between stages IA and IB. The 5-year overall survival was worse in high-grade endometrial stromal sarcoma than low-grade endometrial stromal sarcoma (45.4% vs. 97.2%, p < 0.001). The difference in 5-year overall survival among women with low-grade endometrial stromal sarcoma between stages IA and IB was significant (100% vs. 93.5%, p = 0.003), but not among women with high-grade endometrial stromal sarcoma (51.4% vs. 43.5%, p = 0.27). Although age ( p = 0.001), race ( p = 0.005), and stage ( p = 0.004) were all significant prognostic factors in low-grade endometrial stromal sarcoma, only cervical involvement ( p = 0.02) was a significant predictor in high-grade endometrial stromal sarcoma. Conclusion The new staging system is appropriate for risk stratification in low-grade endometrial stromal sarcoma. The prognosis in high-grade endometrial stromal sarcoma seems to be most influenced by the presence of cervical involvement and not by tumor size as the staging criteria would suggest.