377 Mini-Invasive (MIS) vs. Open Surgery (OSu): prognostic impact of the surgical approach for endometrial Cancer. A FRANCOGYN collaborative group survey

Introduction/Background* Thanks to technical improvements, total non-conservative hysterectomy evolved towards MIS as the standard approach for early-stage endometrial cancer (EC). MIS has recently been called into question for cervical cancer treatment due to its negative prognosis impact. In this context, we carry out a study comparing OSu vs. MIS with Disease Free Survival (DFS) as primary endpoint. Methodology Retrospective study, within the French collaborative group FRANCOGYN from 1999 to 2020. All patients aged over 18 who achieved hysterectomy for endometrial cancer were included whatever the pathological subtype. Secondary endpoints were: Overall Survival (OS) and sub-group analysis according to FIGO stage, ESMO-ESGO-ESTRO Consensus Conference risk-group 2015 (E3CC), pathological sub-types, lymph node metastasis and lympho-vascular space invasion (LVSI). To assess primary endpoint, we use inverse probability of treatment weighting (IPW) based on propensity score to construct two weighted cohort. A Cox proportional-hazard model standard multivariate analysis was used for subgroup analysis. Result(s)* Nine hundred and forty-five (945) patients were included, 380 (40.2%) received OS and 565 (59.8%) received MIS. The median follow-up was 34.2 months (29.1 SD) . The study other measured characteristics were strongly unbalanced in disfavor of the OSu group for pathological subtype (p DFS was significantly impaired by the following characteristics: Age, BMI, histological grade 3 (HR=2.04, 95% CI [1.15-2.04] p = 0.015), E3CC High Risk Group (HR = 2.62, 95% CI [1.03-6.67] p = 0.43) and FIGO Stage 3 (HR= 2.21, 95% CI [1.07-4.56] p= 0.031) Conclusion* This study cover 20 years of clinical practice and consolidate MIS place for EC surgical treatment with an increasing use of MIS over years whatever the FIGO staging and clinical characteristics. Every effort should be made to improve a standardized MIS approach the more that patient is frail or at high risk of relapse.