Sentinel lymph node biopsy in endometrial cancer: The new norm - A multicentre, international experience.

Objectives: The landscape of early-stage endometrial cancer treatment has changed dramatically over the last decade. The aim of this study is to provide a real-world view of the impact sentinel lymph node (SLN) biopsy has had on both clinical practice and patient outcomes. We describe detection and recurrence rates, as well as our experience in managing low volume lymph node disease.

Methods: We conducted an international, multicenter retrospective cohort study of 1012 patients with apparent early-stage endometrial cancer. Eligible patients underwent primary surgical staging and SLN biopsy in one of three large academic tertiary cancer centers in Canada or the Republic of Korea between 2015 and 2019. Demographic, surgical, clinicopathologic and recurrence data were collected through chart review.

Results: A total of 1012 patients were included. Overall SLN detection rate for all tracer types was 94.1% and recurrence rate was 5.3%. Higher FIGO stage (III vs. I/II) was associated with failed bilateral mapping (OR 2.27, 95%CI 1.14-4.52). We identified seven patients with micrometastases and 12 with isolated tumor cells, of which only one patient with micrometastases recurred at 17 months. Recurrence rates based on risk groups were 2.1%, 5.3%, 8.1%, and 9.9% for low, intermediate, high-intermediate, and high risk, respectively.

Conclusion: SLN biopsy is safe and feasible. Detection rates are high, regardless of which tracer type is used and recurrence rates are low, especially in low and intermediate risk disease. Patients with low volume metastases appear to have low risk of recurrence, but replication of our findings by large prospective studies are needed to elucidate their clinical importance.