Clinicopathological characteristics and survival outcomes in early-stage endometrial clear cell carcinoma: a dual-center retrospective study

To investigate clinicopathological predictors and evaluate the impact of adjuvant therapy on survival outcomes in patients with early-stage (FIGO 2023 Stage I-II) endometrial clear cell carcinoma (ECCC). This dual-center retrospective study enrolled patients newly diagnosed with stage I-II ECCC between January 1, 2010 and December 31, 2023 at two tertiary hospitals in China. Clinicopathological parameters and survival outcomes were systematically analyzed. Kaplan-Meier curves and Cox regression analyses were used to assess the associations between variables and overall survival (OS) or progression-free survival (PFS). Among 80 eligible patients (median age: 59 years), 30.0% (n = 24) were stage I and 70.0% (n = 56) stage II. After a median follow-up of 76 months, 11 patients experienced disease progression and 6 died, with 5-year PFS and OS rates of 87.0% and 91.6%, respectively. Kaplan-Meier survival analysis demonstrated no significant differences in PFS or OS between patients undergoing surgery alone versus surgery with adjuvant therapy. Multivariate Cox analysis identified positive peritoneal washing cytology (PWC) (HR = 8.062, 95% CI: 1.208–53.814, P = 0.031) and deep myometrial invasion (≥ 1/2) (HR = 7.455, 95% CI: 1.187–46.803, P = 0.032) as independent adverse prognostic factors for OS. Diabetes mellitus emerged as the only significant predictor for reduced PFS (HR = 3.831, 95% CI: 1.053–13.935, P = 0.042). Positive PWC and deep myometrial invasion (≥ 1/2) were independent adverse prognostic factors for OS in stage I-II ECCC, while diabetes mellitus emerged as the sole predictor of poorer PFS. Notably, adjuvant therapy failed to demonstrate any significant survival benefit compared to surgery alone in this cohort. These findings challenge the routine use of adjuvant therapy for stage I-II ECCC and underscore the importance of individualized risk stratification incorporating PWC, myometrial invasion depth and diabetic status.