Endometrial cancer is the most common gynecologic malignancy in the industrialized world, with an estimated 320,000 cases diagnosed annually worldwide [1]. In the United States, nearly 60% of new cases are attributable to being overweight or obese, with a 7 times greater risk for body mass index (BMI kg/m2) > 40 [2, 3]. It is estimated that up to 81% of patients with endometrial cancer have BMI > 30 and 19-36% have BMI ≥ 40 [4]. Obesity is also associated with higher disease-specific mortality among patients with endometrial cancer, regardless of initial stage or grade of disease [5].

The National Comprehensive Cancer Network (NCCN) recommends sentinel lymph node (SLN) mapping in patients with clinical stage 1 disease [6]. Compared to laparotomy, minimally invasive surgery for endometrial cancer staging has mitigated some of the technical and anesthetic challenges of surgery for obese patients, a population at risk for omitted nodal assessment, while also improving SLN mapping success for all comers [7, 8, 9, 10].

There is evidence that increasing BMI is associated with decreased rates of SLN mapping. In a recent study by Vargiu et al. evaluating the impact of obesity on SLN mapping, the higher BMI group (≥ 30) had significantly lower rates of overall detection, bilateral mapping, and higher rates of mapping failure. Their data show only 75 out of 764 subjects (9.8%) had a BMI ≥ 40 [11]. This study evaluates success rates of SLN mapping in patients with BMI ≥ 45, as this population remains understudied.