Lymphatic mapping and obesity with sentinel lymph node biopsy in endometrial cancer

Abstract

<h3>Objectives:</h3> Sentinel lymph node biopsy (SLNB) has emerged as an acceptable alternative to complete pelvic and paraaortic lymph node dissection (PPALND) for patients with clinical stage I endometrial cancer. Several factors are associated with high risk of bilateral SLN detection failure. Our aim is to investigate the effect of obesity on bilateral SLN detection rates. <h3>Methods:</h3> Patients with either clinical stage I endometrial cancer or complex atypical hyperplasia were retrospectively reviewed from September 2016 through February 2020. All patients had undergone either a robot-assisted or laparoscopic hysterectomy with SLNB. Endometrioid, uterine papillary serous (UPSC), malignant mixed mesodermal tumor (MMMT), and clear cell (CC) histologies were included. Indocyanine green was injected into the cervix per our protocol. Patients with suboptimal lymph node mapping or nodes suspicious for metastasis underwent a side specific pelvic lymph node dissection (LND). In addition to SLNB, PPALND was performed for patients with UPSC, MMMT, and CC. Sentinel lymph nodes (SLN) were evaluated using ultra-staging protocols including serial sectioning and cytokeratin staining. The medical record was queried for successful bilateral or unilateral sentinel lymph node detection. Patient demographic data was then collected and analyzed with sentinel lymph node detection rate. <h3>Results:</h3> A total of 97 patients were reviewed and included: 92 had diagnosed endometrial cancer while 5 had complex atypical hyperplasia. Stage were as follows: 81 patients had stage I or II disease, and 8 patients had Stage III disease diagnosed at surgery. At least one SLN was detected 95.9% of cases, with an overall bilateral detection rate of 77.7%. In total, 53 patients classified as obese (25 Class I, 15 Class II and 13 Class III), 24 patients were overweight (BMI 25-29.9) and 20 patients had normal BMI. Unilateral and bilateral detection rates were not independently associated with obesity class. Bilateral SLN detection rates were 76% in normal BMI class and 67%, 83% and 73% for Class I, Class II and Class III obesity respectively; while at least one SLN was detected in 94% of normal BMI class and 92%, 96%, 100% and 92% in overweight weight class, Class I, II and II obesity respectively. <h3>Conclusions:</h3> Patient BMI is an important consideration for preoperative planning and success of bilateral sentinel lymph node mapping. Bilateral detection rates among obese patients are comparable to those of non-obese patients in our cohort. Despite previously reported correlation between BMI and successful bilateral mapping, our results do not demonstrate this relationship and obesity does not appear to be a contraindication to SLNB.