A comparison of uterine papillary serous, clear cell carcinomas, and grade 3 endometrioid corpus cancers using 2009 FIGO staging system

OBJECTIVE: This study was designed to compare survival outcomes of patients with uterine papillary serous carcinoma (UPSC) or clear cell carcinoma (CC) to those of patients with grade 3 endometrioid carcinoma (G3EC) according to 1988 and 2009 International Federation of Gynecology and Obstetrics (FIGO) staging systems. METHODS: We retrospectively reviewed all patients with endometrial cancer treated at a single institution between 1995 and 2009. Among the 647 patients with endometrial cancer, 51 with G3EC and 46 with UPSC and CC histology were confirmed. RESULTS: 1988 FIGO stage, 2009 FIGO stage, and extrauterine metastasis were significantly different between the UPSC and CC group and G3EC group (p=0.002, p=0.041, and p=0.020, respectively). Restaging from the 1988 FIGO to the 2009 FIGO criteria increased the number of stage I cases by 10 (11.0%). Overall, 8 in the UPSC and CC and 2 in the G3EC group were down-staged to stage I. In the UPSC and CC group, the 3-year overall survival for 1988 FIGO stage I was 92.9%. When UPSC and CC patients were restaged using the 2009 staging system, the 3-year overall survival of 2009 FIGO stage I dropped to 81.6%. UPSC and CC was associated with poor OS outcome compared with G3EC, after adjustment for 2009 FIGO stage and other clinicopathologic factors. CONCLUSION: We observed that UPSC and CC patients had different prognosis according to the old and new FIGO staging system. Our results suggest that UPSC and CC compared with the G3EC may retain the 1988 FIGO to be a slightly better discriminator than 2009 FIGO.