Preliminary study on the intraoperative application of the “dual-path” strategy for sentinel lymph node tracing in endometrial cancer

Abstract

Abstract At present, in endometrial cancer surgery, sentinel lymph node tracing via cervical tracer injection is mainly used to assess the metastatic status of pelvic lymph nodes, but it is difficult to evaluate the metastatic status of para-aortic lymph nodes. This study aimed to explore the feasibility of tracing pelvic and para-aortic sentinel lymph nodes drained through different pathways by injecting different tracers via the cervix and proper ovarian ligament respectively during endometrial cancer surgery.A total of 32 patients with endometrial cancer who underwent laparoscopic surgery at the Affiliated Cancer Hospital of Guangxi Medical University from January 2024 to January 2026 were enrolled as the research subjects. Methylene blue solution was injected via the cervix to visualize pelvic sentinel lymph nodes, while indocyanine green (ICG) was injected via the proper ovarian ligament to visualize para-aortic sentinel lymph nodes. The visualization status of sentinel lymph nodes was observed.All sentinel lymph nodes (SLNs) visualized by cervical injection of methylene blue were confined to the pelvic cavity: 92% of lymphatic drainage followed the upper paracervical pathway (UPP), with SLNs located in the obturator and external iliac regions; 8% followed the lower paracervical pathway (LPP), with SLNs in the common iliac region; no infundibulopelvic ligament pathway (IPP) was detected.ICG injection via the proper ovarian ligament visualized SLNs draining through the IPP. The time to initial SLN visualization ranged from 10 s to 137 s (median, 45 s; mean, 50.9 s). Left-sided SLNs were situated in the para-aortic region between the inferior mesenteric artery and left renal vein, with a visualization rate of 80.6% and an accuracy of 95.8%. Right-sided SLNs were located on the inferior vena cava surface 2–3 cm above the aortic bifurcation, with a visualization rate of 93.8% and 100% accuracy. There was no overlap between the visualization pathways of methylene blue and ICG. One case of postoperative lymphatic fistula occurred. The “dual-path” strategy—using different tracers injected via the cervix and proper ovarian ligament to visualize pelvic and para-aortic SLNs respectively—is feasible in endometrial cancer surgery, enabling more comprehensive and accurate assessment of lymph node metastatic status.