19 A prospective study comparing histological and molecular features in predicting the risk of nodal disease in endometrial cancer

Introduction/Background To assess the role of histopathological and molecular features in predicting the risk of nodal metastases in apparent early-stage endometrial cancer patients undergoing sentinel node mapping. Methodology This is a prospective multicenter trial (Clinical trial registration: NCT05793333). Consecutive patients with apparent early-stage endometrial cancer undergoing hysterectomy, bilateral salpingo-oophorectomy, and sentinel node mapping were enrolled. Histological and molecular features were used to predict the node positivity. Results Charts of 210 apparent early-stage endometrial cancer patients were evaluated. The study population included 178 (85%%) and 32 (15%) patients with endometrioid and non-endometrioid endometrial cancer, respectively. According to conventional pathological uterine characteristics, 94 (44%), 46 (22%), 41 (19%), and 32 (15%) were classified as low, intermediate, intermediate-high, and high-risk, respectively. According to molecular classification 10 (5%), 42 (20%), 57 (27%), and 101 (48%) were included in the POLE mutated, p53 abnormal, MMRd/MSI-H, and NSMP, respectively. Overall, 41 (19%) patients were detected with positive nodes. Pathological characteristics were more likely to predict nodal status instead of molecular features. Molecular features were not associated with the risk of having nodal metastases (OR: 1.03 (95%CI: 0.21, 5.95; p=0.969) for POLE mutated; OR: 0.788 (95%CI: 0.32, 1.98; p=0.602) for p53 abnormal; OR: 1.14 (95%CI: 0.53, 2.42); p=0.733 for MMRd/MSI-H). At multivariate analysis, only deep myometrial invasion (OR: 3.33 (95%CI: 1.40,7.80); p=0.006) and LVSI (OR: 6.03 (95%CI: 2.56, 15.4); pConclusion Our prospective study suggested that molecular features seem not useful to tailor the need for nodal dissection in apparent early-stage endometrial cancer. Further external validation is needed. Disclosures None.