Intraabdominal lymphatic mapping to direct selective pelvic and paraaortic lymphadenectomy in women with high-risk endometrial cancer: Results of a pilot study

Objective: To determine the feasibility of intraperitoneal lymphatic mapping of the uterine fundus as a means of identifying target sites for lymph node biopsy during staging laparotomy and to develop preliminary experience with the technique. Methods: Fifteen women with high-risk endometrial tumors were entered on this Institutional Review Board-approved pilot study. At laparotomy, isosulfan blue dye (1.0 ml) was injected into the subserosal myometrium at three sites: the superior midpoint of the fundus, 2 cm inferiorly on the anterior wall, and 2 cm inferiorly on the posterior wall. Dye uptake into lymphatic channels was observed for 10 min. The retroperitoneal spaces were opened. Blue lymphatic channels and nodes within the pelvic and paraaortic regions were identified. Nodes demonstrating dye uptake were biopsied as separate specimens: the locations of these nodes were carefully recorded. Hysterectomy and selective lymphadenectomy were then performed as usual. Results: Lymphatic channels coursing into the broad ligament and along the ovarian vessels were identified from all uteri injected. Deposition of dye into grossly identifiable lymph nodes was seen in 10 of 15 cases (67%). A total of 31 nodes demonstrated dye uptake. The locations of these nodes included paraaortic sites in 12, common iliac in 6, and pelvic in 13. No dye- containing paraaortic nodes were seen below the origin of the inferior mesenteric artery. Lymphatic channels coursing above the renal vessels were seen routinely. Microscopic nodal metastases to sentinel nodes were identified in 2 of 4 women with proven lymphatic spread. Conclusions: Lymphatic mapping of the uterine fundus is feasible and can identify targets for selective nodal biopsy in some women. Preliminary observations confirm that the lymphatic network draining the uterus is complex and involves both pelvic and paraaortic nodes. Lymphatic channels that parallel the ovarian vessels were not observed to enter nodes until reaching the level of the midabdomen. Further experience and refinement of techniques may lead to the development of a selective lymphadenectomy based upon direct visualization of the lymphatic drainage of the uterus rather than the current random sampling.