Introduction Compared with other pathological types, the prognosis of ovarian endometrioid carcinoma (OEC) is better. The treatment of OEC follows the general principles of epithelial ovarian cancer treatment, with comprehensive staging surgery and tumor reduction surgery. However, patients underwent lymphadenectomy may affect their quality of life. This study investigated the value of lymph node dissection in improving the prognosis of early stage OEC patients and sought the optimal number of lymph node resections.

Methods We collected and organized the clinical and pathological materials of 2717 postoperative patients with stage I OEC in the SEER database from 2004 to 2018. Uni- and multi- Cox regression models were used to screen for the independent risk factors and divide patients into subgroups. Kaplan-Meier was used for survival analysis in subgroups to explore the relationship between lymph node dissection and survival in stage I OEC patients. We used Cox regression combined with restricted cubic spline (RCS) function to analyze the optimal number of lymph node dissections (LNN).

Results Age, marital status, tumor size, histological grade, and lymphadenectomy are independent risk factors affecting the overall survival (OS) of stage I OEC patients. Patients who underwent lymphadenectomy had an improved OS compared to those who did not. Cox regression analysis and restrictive cubic spline function analysis suggests that when LNN is 21, patients receive the best survival benefit.

Conclusion/Implications Lymphectomy can improve the prognosis of stage I OEC patients, and we recommend 21 LNNs as the entry point for evaluating the stratification of prognosis in stage I OEC patients.