Morbid obesity increases the failure rate of sentinel lymph node mapping for endometrial carcinoma

Abstract

<h3>Objectives:</h3> Sentinel Lymph Node (SLN) mapping is recommended for patients with endometrial carcinoma to reduce the rate of full lymphadenectomy and its associated morbidity such as lymphedema. Obesity is a risk factor for endometrial carcinoma, and many patients are morbidly obese at the time of diagnosis. The goal of this study is to examine the impact of body mass index (BMI) on the success rate of SLN mapping using indocyanine green (ICG) and near-infrared imaging. <h3>Methods:</h3> A retrospective cohort study was performed of women with endometrial carcinoma undergoing robotic hysterectomy and SLN mapping with ICG between March 2016 and August 2019. Robotic surgery cases were identified from the hospital financial system that were coded with a primary diagnosis of Endometrial Cancer, a procedure of hysterectomy, and a cost code for indocyanine green. A total of 369 cases were identified. A total of 28 cases were excluded because no dye was used or SLN mapping was not attempted due to extent of disease. Preoperative patient characteristics and surgical outcomes including SLN mapping success rate were compared across World Health Organization BMI groups. <h3>Results:</h3> BMI was categorized as normal weight (BMI 18.5 - 24.9, 41 patients), pre-obesity (BMI 25.0 - 29.9, 48 patients), obesity class I (BMI 30.0 - 34.9, 71 patients), obesity class II (BMI 35.0 - 39.9, 70 patients), and obesity class III (BMI ≥40, 111 patients). Across BMI groups, patient age and ASA category were significantly different, with younger ages and higher ASA scores in the higher BMI groups. BMI groups did not differ in the number of prior abdominal surgeries or FIGO Grade. Uterine weight, diameter and procedure time were all significantly different across BMI groups, with higher weights, diameters and procedure times in the higher BMI groups. Estimated blood loss and depth of myometrial invasion were not significantly different. In the cohort, 85% had FIGO Stage 1 disease. For procedures with successful unilateral or bilateral SLN detection, the mean number of lymph nodes removed per side was not significantly different across BMI groups. The overall bilateral SLN mapping success rate for the cohort was 68.9%. However, the bilateral SLN mapping success rate was significantly lower in patients with obesity class III (54.1%) compared with patients who were less obese (76.1%, p<0.01). There was no difference in success rate between lower BMI categories. <h3>Conclusions:</h3> Patients with class III obesity (BMI > 40) have a significantly lower success rate for SLN mapping when compared with all other BMI categories (54.1% vs 76.1%, respectively, p<0.01).