Sentinel lymph node mapping in endometrial cancer: new insights into an essential tool

ABSTRACT

Objective. This narrative review summarizes current evidence on sentinel lymph-node (SLN) mapping in endometrial cancer (EC), focusing on tracer performance, injection techniques, detection rates (DR), surgical approaches, and ultrastaging.

Study selection. A comprehensive search of PubMed, Embase, and the Cochrane Library was performed (inception – 15 April 2025) using the terms “sentinel lymph node” AND “endometrial cancer”, without year limits. Studies, guidelines, and technical reports addressing SLN mapping in EC were screened, and data were extracted narratively according to SANRA recommendations.

Results. Three tracer classes are routinely employed: indocyanine green (ICG, near-infrared), technetium-99m colloid (radio-nuclear), and methylene blue (colourimetric). Cervical ICG injection—administered superficially and deeply at 3- and 9-o’clock or in four quadrants—achieves the highest reported bilateral DR (≈ 93–98 %). At the same time, intra-operative re-injection can raise the DR by a further ~5 %. Hysteroscopic and trans-myometrial (TUMIR) routes improve para-aortic visualisation but are technically more demanding and yield lower pelvic DRs. Combining ICG with technetium or methylene blue offers no consistent advantage over ICG alone. Minimally invasive approaches (laparoscopy, robotics, single-site surgery) maintain high DRs (91–95 %) and reduce postoperative morbidity compared with laparotomy. Application of serial-section ultrastaging with cytokeratin immunohistochemistry identifies an additional 3–4 % of micrometastases or isolated tumour cells relative to routine haematoxylin–eosin evaluation.

Conclusions. SLN biopsy provides an accurate nodal assessment while sparing patients the morbidity associated with systematic lymphadenectomy. Cervical ICG injection, coupled with minimally invasive surgery and meticulous ultrastaging, currently represents the most effective and reproducible strategy for SLN mapping in EC. Further standardisation of para-aortic mapping techniques and pathological protocols will refine staging accuracy and guide adjuvant treatment decisions.