Predicting the Risk of nOdal disease with histological and Molecular features in Endometrial cancer: the prospective PROME trial

Objective 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. Methods This is a prospective trial. Consecutive patients with apparent early-stage endometrial cancer, undergoing laparoscopic hysterectomy, bilateral salpingo-oophorectomy, and sentinel node mapping, were enrolled. Histological and molecular features were used to predict the node positivity. Results Charts of 223 apparent early-stage endometrial cancer patients were included in this study. Four (1.8%) patients were excluded from this study due to the lack of data about molecular features. Additionally, nine (4%) patients did not meet the inclusion criteria (due to the presence of peritoneal carcinomatosis or bulky nodes (the presence of p53 abnormality correlated with the presence of advanced stage disease (p<0.001)). The study population included 178 (84.8%) and 32 (15.2%) patients with endometrioid and non-endometrioid endometrial cancer, respectively. According to pathological uterine risk factors, 93 (44.3%), 45 (21.4%), 40 (19.1%), and 32 (15.2%) were classified as low, intermediate, intermediate-high, and high-risk, respectively. Using the surrogate molecular classification, 10 (4.8%), 42 (20%), 57 (27.1%), and 101 (48.1%) 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 to 5.05, p=0.969 for POLE mutated; OR 0.788, 95% CI 0.32 to 1.98, p=0.602 for p53 abnormal; OR 1.14, 95% CI 0.53 to 2.42, p=0.733 for MMRd/MSI-H). At multivariable analysis, only deep myometrial invasion (OR 3.318, 95% CI 1.357 to 8.150, p=0.009) and lymphovascular space invasion (OR 6.584, 95% CI 2.663 to 16.279, p<0.001) correlated with the increased risk of positive nodes. Conclusion Our data suggest that molecular classification does not seem useful to tailor the need of nodal dissection in apparent early-stage endometrial cancer. p53 abnormality predicts the risk of having advanced disease at presentation. Further external validation is needed.