Lymphadenectomy and chemotherapy are effective treatments for patients with 2023 international federation of gynecology and obstetrics stage IIC-high risk endometrial cancer in Japan

Background: In early-stage endometrial cancer (EC), the treatment of aggressive histological subtypes (endometrioid carcinoma grade 3, serous carcinoma, clear-cell carcinoma, undifferentiated carcinoma, mixed carcinoma, and carcinosarcoma) is controversial. We aimed to investigate the treatment of patients with International Federation of Gynecology and Obstetrics (FIGO) stage IC and stage IIC EC according to the 2023 classification.

Methods: We retrospectively identified patients with FIGO 2023 stage IC, IIC-intermediate risk (IIC-I), and IIC-high risk (IIC-H) EC who underwent adjuvant therapy or observation after surgery at eight medical institutions from 2004 to 2023. Progression-free survival (PFS) and overall survival (OS) were evaluated using Kaplan-Meier estimates and univariate and multivariate analyses.

Results: The PFS and OS were significantly worse in patients with FIGO 2023 stage IIC-H EC than in those with FIGO 2023 stage IIC-I EC (PFS: p = 0.008 and OS: p = 0.006). According to the FIGO 2023 stage IIC-H classification, lymphadenectomy and chemotherapy resulted in better prognoses regarding both PFS and OS (p < 0.001 for both) than other treatments. Our findings suggest that lymphadenectomy and chemotherapy effectively reduced vaginal stump and lymph node metastases in FIGO 2023 stage IIC-H EC (p < 0.001 and p = 0.008, respectively). Furthermore, in the multivariate analysis, not undergoing lymphadenectomy or chemotherapy were independent predictors of recurrence and poor prognoses in patients with FIGO 2023 stage IIC-H EC (p < 0.001 and p = 0.031, respectively).

Conclusion: Lymphadenectomy and chemotherapy resulted in better prognoses regarding both recurrence and survival in patients with FIGO 2023 stage IIC high-risk EC.