Differential Impact of Systemic Lymphadenectomy Upon the Survival of Patients with Type I vs Type II Endometrial Cancer: A Retrospective Observational Cohort Study

PURPOSE: To determine whether systemic lymphadenectomy exerts a similar effect on the survival of patients with either type I or type II endometrial cancer (EC). PATIENTS AND METHODS: In this retrospective study, 682 eligible patients diagnosed with EC were typed according to the pathological reports. The thoroughness of lymphadenectomy was evaluated by the lymph node number of which the cut-off value was determined by the receiver operator characteristic (ROC) curve and Youden index. The impact of thoroughness on the survival of both types was analyzed, respectively, by Kaplan Meier (K-M) method and further evaluated in subgroups with and without lymphatic metastasis. Independent prognostic factors of survival were selected by proportional hazard regression (Cox) model. RESULTS: The cut-off level of lymph node number was 20. The differential impact of the lymph node number removed on survival was noted when patients with different types were analyzed separately. Among type II EC, those with >20 lymph nodes removed presented better overall survival (OS) than those with ≤20 (p=0.002). The number of lymph nodes removed >20 was proved as an independent factor for improved OS in type II EC (HR=0.329,95% CI: 0.123–0.881, p=0.0027). In the subgroup of type II with >20 lymph nodes resected, similar 5-year OS rates were observed in those with or without identified positive node (90.9% vs 92.9%, p=0.965). Type I EC seemed unbeneficial from such a procedure. CONCLUSION: Systemic lymphadenectomy could enhance the OS of type II EC other than type I.