Does the FIGO 2009 endometrial cancer staging system more accurately correlate with clinical outcome in different histologies? Revised staging, endometrial cancer, histology.

Objective: In 2009, the International Federation of Gynecology and Obstetrics (FIGO) staging system was revised for endometrial cancers. Different histologies were examined in a large population database. The FIGO 1988 and 2009 staging systems were compared for stage at presentation, differences in patient populations, and disease-specific survival (DSS).

Methods/materials: A total of 10,839 cases from 1998 to 2006 were analyzed from the Surveillance, Epidemiology, and End Results (SEER) Program. Examined histologies included 1377 cases of clear cell carcinoma (CC), 2304 cases of uterine papillary serous carcinoma (PS), 755 cases of carcinosarcoma (CS), and 6403 cases of grade 3 endometrial adenocarcinoma (G3A). The median follow-up was 26 months. For each stage and histology, DSS for patient characteristics was examined.

Results: Of the 10,839 women with CC, PS, CS, and G3A had a median age of 67 years. White, black, and other ethnicities composed 87.5%, 12%, and 7% of this group, respectively.A higher percentage of non-G3A histology (CS, PS, and CC) was found in 58% of black women versus 39% of white women. The best to worst 5-year DSS was G3A (76.2%), CC (68.8%), PS (59%), and CS (53.4%). Patients with FIGO IIIC2 disease had inferior survival outcomes in CC (P = 0.0079) and G3A (P = 0.047) compared with FIGO IIIC1 disease, whereas DSS was not significantly different for CS and PS between stages IIIC1 and IIIC2.

Conclusions: These findings describe differences in the DSS of various aggressive histologies of EC, with poorer DSS in PS, CC, or CS histologies. Analysis demonstrated the usefulness of the new FIGO staging for DSS prediction between stages IIIC1 and IIIC2 for CC and G3A, and 2 divisions for stage I rather than three.