Analysis of lymph node metastasis and risk factors in 424 patients with low-grade endometrioid endometrial carcinomas.

Objectives: Objectives: To explore the lymph node metastasis (LNM) and related risk factors of low-grade endometrioid endometrial carcinomas (EEC), and analyze the efficacy of related risk factors in predicting LNM.

Design: Data from 424 patients with low-grade EEC treated between January 2019 and June 2024 were retrospectively analysed, according to the International Federation of Gynecology and Obstetrics (FIGO) 2009.

Methods: Univariate and multivariate logistic regression analyses were used to examine the factors associated with LNM. Receiver operating characteristic (ROC) curves were plotted to assess the predictive efficacy of independent risk factors for LNM.

Results: The rate of LNM was 7.8% (33/424). Histological grade, tumour size, depth of myometrial invasion, cervical stromal invasion, lymphovascular space invasion (LVSI), microcystic, elongated, fragmented (MELF) pattern, carbohydrate antigen 125 (CA125), carbohydrate antigen 199 (CA199), and human epididymis protein 4 (HE4) were associated with LNM. However, only LVSI, MELF pattern, depth of myometrial invasion, and CA125 were identified as independent risk factors. The area under the ROC curve (AUC) for CA125 and depth of myometrial invasion was 0.796 and 0.734, respectively. The optimal cut-off value for CA125 was 31.36 U/mL, with a maximum Youden index of 53.9%. Combining CA125 with depth of myometrial invasion improved diagnostic accuracy compared to either parameter alone.

Limitations: Retrospective nature of the study and limitation to a singlecenter study.

Conclusions: LNM is more likely with independent risk factors. Combining CA125 and depth of myometrial invasion enhances diagnostic accuracy for LNM. This study provides valuable insights for predicting LNM risk in low-grade EEC patients and guiding stratified management.