Surgery for patients with endometrioid-type endometrial cancer: is lymphadenectomy above the inferior mesenteric artery necessary?

The primary objective of this study was to identify the risk of metastasis to lymph nodes above the inferior mesenteric artery (IMA) in endometrioid-type endometrial cancer (EC) and the factors that influence metastasis. The study included patients who had been operated on for endometrioid-type EC in three gynecological oncology centers between 2007 and 2023. The supramesenteric lymph node (SM-LN) is the region between the left renal vein and the IMA, whereas the inframesenteric lymph node (IM-LN) is the region between the IMA and the aortic bifurcation, as determined by the level of the IMA. The study sample comprised 412 patients. The median number of lymph nodes excised per patient was 58. The median count was 37 for pelvic lymph nodes, 21 for para-aortic lymph nodes, 8 for IM-LN, and 13 for SM-LN. In the univariate analysis, the factors that were found to be statistically significant in determining SM-LN metastasis included tumor size, depth of myometrial invasion, uterine serosal invasion, lymphovascular space invasion (LVSI), cervical invasion, peritoneal cytology, adnexal metastasis, omental metastasis, non-nodal extrauterine metastasis, pelvic lymph node metastasis, and IM-LN metastasis. In the multivariate analysis, SM-LN metastasis was independently associated with tumor size, LVSI, pelvic lymph node metastasis, and IM-LN metastasis. In conclusion, in cases of intermediate-high risk EC, it is important to know that the disease spreads to SM-LN in 7.3% of patients. The efficacy of postoperative adjuvant treatment may be inadequate due to a lack of information regarding the SM-LN region.