Abstract LB-71: Stage Ia vs. Ib endometrial stromal sarcoma: Does the new staging system predict survival

Abstract

Abstract Background: In 2008, a new FIGO staging system was specifically designed and approved for endometrial stromal sarcoma. Our objective was to determine the impact of this new staging system on survival in patients with stage I endometrial stromal sarcoma (ESS). 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, with 310 (67%) low-grade endometrial stromal sarcoma (LGESS), 96 (21%) high-grade endometrial stromal sarcoma (HGESS), and 58 (12%) unclassified ESS. LGESS compared to HGESS differed significantly with regards to the patient age (48 vs. 60 years, p<0.001), tumor size (5.6 cm vs. 8.0 cm, p<0.001), cervical involvement (5.2% vs. 18.8%, p<0.001), myometrial invasion (62% vs. 66.6%, p=0.01), and stage IB disease (44% vs. 76%, p<0.001). Similarly, compared with LGESS, a greater percentage of HGESS patients underwent lymphadenectomy (29.0% vs. 60.4%; P <0.001), salpingo-oophorectomy (78.4% vs. 93.7%, p=0.001), and administration of radiotherapy (14.8% vs 50.0%; P<0.001). There was no significant difference between stages IA and IB with regards to the above-mentioned demographic and clinico-pathologic variables, in both LGESS and HGESS. The 5-year overall survival was worse in HGESS than LGESS (45.4% vs. 97.2%, p<0.001). The difference in 5-year overall survival between stages IA and IB was significant in LGESS (100% vs. 93.5%, p=0.003), but not in HGESS (51.4% vs. 43.5%, p=0.2). Although age (p=0.001), race (p= 0.005), stage (p=0.004) were all significant prognostic factors in LGESS, only cervical involvement (p=0.02) was a significant predictor in HGESS. Conclusion: The new staging system is appropriate for risk stratification in LGESS. The prognosis in HGESS seems to be most influenced by the presence of cervical involvement and not by tumor size as the staging criteria would suggest. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-71.