Sentinel Lymph Node Mapping in Endometrial Cancer: An Update

 Lymph node removal for staging, as part of the initial surgical management of patients with endometrial carcinoma, remains a controversial topic in gynecologic oncology. There is currently wide variability among clinical practices, with surgical approaches ranging from no nodal evaluation to comprehensive pelvic and aortic lymphadenectomy. Lymphatic mapping has emerged as an increasingly popular option over the past few years, with several attractive features in its concept, innovative surgical approach, and encouraging preliminary results. At this time, however, several different techniques have been described and used for lymphatic mapping in endometrial cancer, incorporating a variety of mapping agents and injection sites. Although recently published results are encouraging, they are limited to single-institution series or multi-institutional collaborations undertaken without the aegis of a prospective randomized controlled trial. However, the surgical staging of endometrial cancer with lymphadenectomy was historically established based not on randomized trial data but on prospective clinicopathologic studies. Another evolving field in endometrial cancer staging is the interpretation of pathologic ultrastaging of sentinel lymph nodes (SLNs), which can identify low-volume metastases for which the clinical significance and the ideal management remain uncertain. This is particularly an issue with extremely low-volume nodal metastasis and isolated tumor cells. Furthermore, it has become apparent that applying a predefined SLN algorithm can decrease false-negative rates. The Memorial Sloan Kettering Cancer Center SLN algorithm can be used as a checklist to ensure standardization of care and to reduce the chance of missing nodal disease. Prospective trials are under way at many institutions to help establish the definitive role of SLN mapping for staging of endometrial cancer. The objective of this study was to provide an update on the latest clinical data related to lymphatic mapping for the staging and management of endometrial cancer and its role in clinical practice.

Implications for Practice:

Lymphatic mapping is an increasingly popular option in the surgical treatment of endometrial cancer. The aim of using this tool is to target the lymph nodes that are the most likely to be involved with metastatic cancer cells (sentinel lymph nodes) and thereby limit the extent of surgery needed and decrease surgical complications and long-term side effects associated with extensive lymph node removal. By examining a limited number of sentinel lymph nodes, a more detailed examination of the node can be done (ultrastaging). This allows for the detection of a small number of cancer cells (low-volume metastasis) that can be missed with standard techniques.