Abstract: Objective: To investigate the high-risk factors of retroperitoneal lymph nodes metastasis (LNM) and the effect of lymph nodes metastasis on prognosis in patients with endometrial carcinoma (EM). Methods: Retrospective research were carried out from January 2005 to December 2010 to identify 289 endometrial cancer patients treated with retroperitoneal lymphadenectomy at Peking Union Medical College Hospital. The high-risk factors of retroperitoneal LNM and prognostic factors of this disease were studied. Results: (1) The median age of at diagnosis was 55 years. Patients of stage I, II, III and IV were 224 (77.5%), 13 (4.5%), 45 (15.6%) and 7 (2.4%), respectively. Two hundred and eighty-nine patients received pelvic lymphadenectomy, of that 30 (10.4%) patients were found the pelvic LNM. Ninety-six patients received periaortic lymphadenectomy, of that 11 (11.5%) patients were found the periaortic LNM. Twenty-one (7.3%) patients developed recurrent disease and 11 (3.8 %) were dead. The median follow-up was 37 months and the median disease-free survival (DFS) was 34 months. (2) In univariate analysis, the incidence of LNM significantly increased in patients with CA125 ≥ 35u/L preoperatively , non-endometrioid adenocarcinoma, low grade, deep myometrium invasion, diameter of tumor ≥ 2cm, cervical stroma involvement, positive peritoneal cytology and vagina or parametrial involvement (P ＜ 0.05). In multivariate analysis, CA125 ≥ 35u/L preoperatively, low grade, deep myometrium invasion was the independent high-risk factors of LNM (P ＜ 0.05). (3) The Kaplan-Meier analysis showed a significant difference between positive peritoneal cytology, vagina or parametrial involvement, appendix involvement, LNM and DFS (P ＜ 0.05). We also found a significant difference on the impact of non-endometrioid adenocarcinoma, low grade, deep myometrium invasion, positive peritoneal cytology, appendix involvement and LNM on overall survival (OS) (P ＜ 0.05). Cox regression analysis revealed retroperitoneal LNM is the independent prognostic factor of 5-year DFS (patients without LNM 92.1% vs patients with LNM 65.3%, P=0.002, 95%CI 0.078-0.552). We also found the trend that the 5-year OS was higher in patients without LNM than them with LNM, even though there was no significant difference (patients without LNM 96.1% vs patients with LNM 70.0%, P=0.086, 95%CI 0.039-1.238). Conclusion: Our study found that (1) there was the predictive value of low grade and deep myometrium invasion for EC patients with LNM. This finding may give the clinician a guild of lymphadenectomy and lay the foundation for individualized treatment; (2) there was the trend that patients with LNM have poorer prognosis than them without LNM. Therefore, patients with LNM should receive adjuvant therapy to reduce the risk of recurrence.

Key words: Endometrial carcinoma, lymph nodes, High-risk factors, prognosis