806 Impact of obesity on sentinel lymph-node mapping in patients with apparent early-stage endometrial cancer: a propensity-matched multicenter study

Introduction/Background* Obese patients pose both surgical and anesthetic challenges, as their comorbidities contribute to adverse outcomes. In this setting, minimally invasive approach and the introduction of the Sentinel Lymph-Node (SLN) algorithm in endometrial cancer (EC) treatment acquire a particular relevance, allowing to reduce both operative times and surgical difficulties. However, conflicting data exists on the impact of Body Mass Index (BMI) on SLN detection. The primary study endpoint was to investigate the impact of obesity on overall detection rate, bilateral mapping, and mapping failure rate. In addition, we evaluated possible differences in terms of surgical management and ‘empty packet dissection’ rate among the two study groups. Methodology Multicenter, propensity-matched, retrospective study. Data of patients with apparently early-stage EC were retrospectively retrieved. Study population was divided into women with BMI Result(s)* Eight-hundred forty-four women were enrolled in the study. After a 1:1 propensity matched analysis, a total of 764 patients were identified (Group-1 n=382, Group-2 n=382). A 1.156-fold increase in the risk of mapping failure for every 5 units of increase in BMI (OR 1.156, 95% CI 1.033-1.294, p=0.012) was found, with a consequently decrease in bilateral mapping and overall detection rate (respectively OR 0.865, 95% CI 0.773-0.968, p=0.012 and OR 0.785, 95% CI 0.670-0.920, p=0.003) (figure 1). Furthermore, in the group of obese patients, in 25 cases (7.4%) the SLN dissection did not lead to the identification of lymph-node tissue at final histopathological examination (’empty packet dissection’) (Group1 vs Group 2: 3.9% vs 7.4%, p=0.046) (table 1). Conclusion* Controlling for the variables that have been proved to negatively influence the SLN detection rate, BMI was confirmed as a statistically relevant predictor of mapping failure. In addition, obese women had a significantly higher odds of empty packet dissection, which could lead to an un-intended surgical understaging.