Success Rates of Sentinel Lymph Node Mapping for Endometrial Cancer in Patients with Body Mass Index < 45 Compared with Body Mass Index ≥ 45.

STUDY OBJECTIVE: The objective is to evaluate the rate of sentinel lymph node (SLN) mapping in patients with body mass index (BMI [kg/m2]) BMI ≥ 45 compared with < 45. DESIGN: A retrospective chart review. SETTING: Three urban referral-based settings-1 academic and 2 community based. PATIENTS: Patients age ≥ 18 years, with endometrial intraepithelial neoplasia or clinical stage 1 endometrial cancer who underwent robot-assisted total laparoscopic hysterectomy with attempted SLN mapping between January 2015 and December 2021. INTERVENTIONS: Robot-assisted total laparoscopic hysterectomy with attempted SLN mapping. MEASUREMENTS AND MAIN RESULTS: A total of 933 subjects were included: 795 (85.2%) with BMI < 45 and 138 (14.8%) with BMI ≥ 45. Comparing the BMI < 45 with BMI ≥ 45 group, bilateral mapping was successful in 541 (68.1%) vs 63 (45.7%), respectively. Unilateral mapping was successful in 162 (20.4%) vs 33 (23.9%), respectively. Failure to map occurred in 92 (11.6%) vs 42 (30.4%) (p <.001), respectively. Exploratory analysis also suggested an inverse relationship between success rate of bilateral SLN mapping and BMI, with patients with BMI < 20 having bilateral SLN mapping rates of 86.5% and patients with BMI ≥ 61 having rates of 20.0%. The steepest decline in bilateral SLN mapping rates was from BMI group 46 to 50 compared to 51 to 55, at 55.4% to 37.5%, respectively. Adjusted odds ratio (compared with those with BMI < 30) for those in the BMI 30 to 44 group was 0.36 (95% confidence interval 0.21-0.60) and for those in the BMI ≥ 45 group was 0.10 (95% confidence interval 0.06-0.19). CONCLUSION: There is a statistically significant lower rate of SLN mapping in patients with a BMI ≥ 45 than BMI < 45. Understanding the success of SLN mapping in patients with morbid obesity is essential for preoperative counseling, surgical planning, and developing a risk-appropriate postoperative treatment plan.