Anatomical basis of lymph node detection in gynecologic cancers: a review from a surgical perspective

Pelvic and para-aortic lymphadenectomy are associated with increased risk of complications and are responsible for a significant proportion of morbidity and impaired quality of life following surgical management of pelvic malignancies. Sentinel lymph node (SLN) was developed as a trade-off between systematic and no lymphadenectomy to limit morbidity while conserving good oncological staging and outcomes. In this comprehensive review, we aimed to synthetize the anatomical basis of the SLN procedure in patients with pelvic malignancies from a surgical perspective. The reliability of the SLN procedure is based on the knowledge of the dissemination pathways for each type of tumors. The most recent understanding of the uterine lymphatic anatomy defined three consistent channels: an upper paracervical pathway (UPP) with draining medial external and/or obturator lymph nodes; a lower paracervical pathway (LPP) with draining internal iliac and/or presacral lymph nodes and the infundibulo-pelvic pathway (IPP) with a course along the fallopian tube and upper broad ligament via the infundibulo-pelvic ligament to its origin. In patients with endometrial cancer, most SLNs are located on the UPP pathway: obturator and external iliac whereas 80% of the SLNs in patients with cervical cancer are located in the external iliac, interiliac and obturator area. Surgical training is a key step toward improving detection rates and exhaustiveness of SLN research while reducing overall morbidity. This is all the more important that the indications for performing complete lymphadenectomy are becoming increasingly rare.