RT Journal Article SR Electronic T1 #207 The role of histological and molecular features in predicting the risk of nodal disease in endometrial cancer: a prospective study JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A139 OP A140 DO 10.1136/ijgc-2023-ESGO.287 VO 33 IS Suppl 3 A1 Bogani, Giorgio A1 Casarin, Jvan A1 Ghezzi, Fabio A1 Longo, Mariangela A1 Ervas, Elisa A1 Multinu, Franesco A1 Betella, Ilaria A1 Lalli, Luca A1 Raspagliesi, Francesco YR 2023 UL http://ijgc.bmj.com/content/33/Suppl_3/A139.2.abstract AB Introduction/Background To assess the role of histopathological and molecular features in predicting the risk of nodal metastases in apparent early-stage endometrial cancer (EC) patients undergoing sentinel node mapping.Methodology This is a prospective multicenter trial. Consecutive patients with apparent early-stage EC undergoing laparoscopic hysterectomy, bilateral salpingo-oophorectomy, and sentinel node mapping were enrolled. Histological and molecular features were recorded at the final pathological evaluation and were used to predict node positivity.Results Charts of 210 EC patients were evaluated. The study population included 178 (85%) and 32 (15%) patients with endometrioid and non-endometrioid EC, respectively. According to conventional pathological uterine characteristics, 94, 46, 41, and 32 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 (19.5%) patients were detected with positive nodes. 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 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); p<0.001) correlated with nodal status. A nomogram evaluating the impact of pathological and molecular features on nodal status was built (C-index 0.78)Abstract #207 Figure 1 Conclusion Our prospective study suggested that molecular features seem not helpful in tailoring the need for nodal dissection in EC. Further external validation is warranted.Disclosures None