Objective To achieve the full potential of sentinel lymph node (SLN) detection in endometrial cancer, both presumed low- and high-risk groups should be included. Perioperative resource use and complications should be minimized. Knowledge on distribution and common anatomical sites for metastatic SLNs may contribute to optimizing the concept while maintaining sensitivity. Proceeding from previous studies, simplified algorithms based on histology and lymphatic anatomy are proposed.
Methods Data on mapping rates and locations of pelvic SLNs (metastatic and non-metastatic) from two previous prospective SLN studies in women with endometrial cancer were retrieved. Cervically injected indocyanine green was used as a tracer and an ipsilateral re-injection was performed in case of non-display of the upper and/or lower paracervical pathways. A systematic surgical algorithm was followed with clearly defined SLNs depicted on an anatomical chart. In high-risk endometrial cancer patients, removal of SLNs was followed by a pelvic and para-aortic lymphadenectomy.
Results 423 study records were analyzed. The bilateral mapping rates of the upper and lower paracervical pathways were 88.9% and 39.7%, respectively. 72% of all SLNs were typically positioned along the upper paracervical pathway (interiliac and/or proximal obturator fossa) and 71 of 75 (94.6%) of pelvic node positive women had at least one metastatic SLN at either of these positions. Women with grade 1–2 endometroid cancers (n=275) had no isolated metastases along the lower paracervical pathway compared with two women with high-risk histologies (n=148).
Conclusion SLNs along the upper paracervical pathway should be identified in all endometrial cancer histological subtypes; removal of nodes at defined typical positions along the upper paracervical pathway may replace a site-specific lymphadenectomy in case of non-mapping despite tracer re-injection. Detection of SLNs along the lower paracervical pathway can be restricted to high-risk histologies and a full pre-sacral lymphadenectomy should be performed in case of non-display.
- endometrial neoplasms
- lymphatic system
- lymphatic vessels
- SLN and lympadenectomy
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Editor's note This paper will feature in a special issue on sentinel lymph node mapping in 2020.
Contributors The study was designed by JP, MB, BG and CL who also performed the data analyses. All authors contributed to data acquisition and interpretation, writing and revising of the draft and the final approval of the manuscript. The corresponding author confirms he had full access to all data in the study and has the final responsibility for the decision to submit the manuscript. All authors have given their written permission to publish the manuscript in the present form.
Funding The study was funded by Skåne County Councils’s Research and Development Foundation (Grant number REGSKANE 353601 and REGSKANE 632231), Skåne University Hospital donation funds (Grant number 95230) and Radiumhemmets Forskningsfonder (Grant number 174102).
Competing interests JP and CL have received honoraria from Intuitive Surgical for proctoring and lectures in robot assisted surgery, and HF has received honoraria from Intuitive Surgical and Medtronics for similar services.
Patient consent for publication Not required.
Ethics approval The study was approved by the respective Institutional Review Boards (Skåne University Hospital, Dnr 2013/163, Karolinska University Hospital Dnr Ö 7-2017).
Provenance and peer review Commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request providing potentially needed and approved amendments of ethical approvals.