Association between preoperative primary tumor SUVmax on FDG PET-CT and high-risk pathological features for the prediction of lymph node metastases in endometrial cancer

AbstractAim:To evaluate the association between preoperative primary tumor SUVmax on 18F-FDG PET-CT and lymph node metastasis, and to assess its relationship with high-risk pathological features in surgically staged endometrial cancer patients.Materials and Methods: In this retrospective cohort study, 134 patients with histologically confirmed endometrial cancer who underwent preoperative 18F-FDG PET-CT and primary surgical staging were included. Primary tumor SUVmax, clinical, imaging, and histopathological parameters were compared between patients with and without lymph node metastasis. ROC curve analysis and univariable/multivariable logistic regression were performed to identify predictors of nodal metastasis.Results:Lymph node metastasis was present in 16 patients (11.9%). Median SUVmax was significantly higher in the lymph-node-positive group (22.60 vs. 14.56; p = 0.003). SUVmax showed moderate discrimination for lymph node metastasis (AUC 0.733; optimal cutoff ≥21.10; sensitivity 62.5%, specificity 79.7%, negative predictive value 94.0%). Pathological tumor diameter showed the numerically highest AUC (0.822), though DeLong's test revealed no significant pairwise differences among ROC curves. On univariable analysis, SUVmax, tumor diameter, CA125, high grade, non-endometrioid histology, LVSI, deep myometrial invasion, and cervical involvement were significantly associated with nodal metastasis. In the exploratory multivariable model, LVSI remained independently associated (adjusted OR 14.33; p = 0.001), while SUVmax (p = 0.182) and deep myometrial invasion (p = 0.094) lost statistical significance.Conclusion: Primary tumor SUVmax is significantly associated with lymph node metastasis and correlates with high-risk pathological features in endometrial cancer, with a high negative predictive value supporting its role in preoperative risk stratification. While LVSI appeared as the most significant predictor overall, it can only be determined after surgery; in contrast, SUVmax, which is accessible preoperatively, could function as a therapeutically relevant proxy for recognizing high-risk individuals prior to the operation. Larger prospective research is required for confirmation.