Determining Predictive Factors of Para-aortic Lymph Node Involvement in Low-grade Endometrial Cancer

Objectives: The purpose of this study was to determine predictive factors of para-aortic lymph node (PALN) involvement in low-grade endometrial cancer of endometrioid type. These factors may influence treatment algorithms and determine the extent of lymph node dissection in patients with low grade endometrial cancer. Our hypothesis was that tumor size, location, and depth of myometrium invasion may be independent predictors of PALN involvement in low grade endometrial cancer. Methods: A retrospective chart review was performed on patients with grades 1 or 2 endometrial cancer of endometroid type who underwent hysterectomy with lymph node removal from January 1, 2004 to August 1, 2014. Data was evaluated using independent t-tests, Mann Whitney U test, and chi square tests. Sensitivity, specificity, positive and negative predictive values were calculated for tumor size, location, and myometrium invasion in association with PALN and pelvic lymph node (PLN) involvement. Results: A total of 259 patients met the inclusion criteria. Tumor size was not significantly different between positive and negative PALN samples (4.5cm vs 3.5cm, respectively; p=0.29). Location was not significantly different among positive and negative PALN groups, as the majority of patients in both groups had tumors in the fundal region (75% vs 70.5%, respectively; p=1.00). Myometrial invasion was not significantly different between positive and negative PALN groups (48% vs 28%, respectively; p=0.14). Myometrial invasion was significantly different among positive and negative PLN groups (71% vs 26%, respectively. p<0.001). Lymphovascular space invasion (LVSI) demonstrated a significant association with both positive PALN and PLN groups (100% vs 22.31%, and 81.25% vs 19.67%, respectively; p=0.003, <0.001). Conclusions: LVSI may be an independent predictor of both PALN and PLN involvement in low grade endometrial tumors. It remains unclear whether tumor size, location, and myometrial invasion can be used to predict para-aortic nodal involvement in these cases.