Evaluation of Node-RADS for Preoperative Nodal Staging in Endometrial Cancer

Overview

This study assessed the reproducibility and diagnostic accuracy of Node-RADS in preoperative locoregional nodal staging of endometrial cancer using CT and MRI. Six readers with varying experience levels independently evaluated imaging, demonstrating Node-RADS as a promising tool for standardized lymph node assessment. The findings highlight its potential to improve nodal staging accuracy and inter-reader agreement.

Background

Endometrial cancer (EC) is the most common gynecological malignancy in Europe with rising prevalence due to aging populations and obesity. Accurate preoperative nodal staging is critical for tailoring surgical management but remains challenging with current imaging modalities, leading to frequent false positives and negatives. The recently introduced Node-RADS system provides a standardized 1-to-5 Likert scale based on lymph node size and morphology to stratify metastatic risk. Prior to this study, Node-RADS had not been evaluated for EC nodal staging or for inter-reader reproducibility across different expertise levels.

Data Highlights

A retrospective cohort of 165 patients with histologically confirmed EC undergoing preoperative pelvic MRI and CT was analyzed. Six readers (two highly experienced, two intermediate, two poorly experienced) independently scored lymph nodes using Node-RADS criteria. Imaging was performed on 1.5-T MRI and dual-source 128-slice CT scanners with standardized protocols. Surgical nodal staging and pathology served as the reference standard. Inter-reader reproducibility and diagnostic accuracy metrics were calculated.

Key Findings

• Node-RADS demonstrated good inter-reader reproducibility across readers with different experience levels, supporting its robustness.
• Both CT and MRI allowed effective application of Node-RADS criteria, with MRI providing better visualization of morphological features such as necrosis.
• Node-RADS categories 1 and 2 correlated well with node-negative status, while categories 4 and 5 correlated with node-positive status, confirming its risk stratification validity.
• Equivocal category 3 required contextual interpretation based on primary tumor characteristics to optimize diagnostic accuracy.
• Dedicated training improved consistency among less experienced readers, indicating the importance of education for reliable Node-RADS use.

Clinical Implications

Node-RADS offers a standardized, reproducible framework for preoperative nodal assessment in endometrial cancer, potentially reducing variability in imaging interpretation. Incorporating Node-RADS into clinical practice may enhance surgical planning by better identifying patients with nodal metastases. Training programs are recommended to ensure consistent application across radiologists with varying expertise.

Conclusion

Node-RADS is a promising tool for improving the accuracy and reproducibility of preoperative locoregional nodal staging in endometrial cancer using CT and MRI. Its implementation could support more tailored surgical approaches and better patient outcomes.

References

1. Elsholtz et al. 2021 -- Introduction of Node-RADS for Lymph Node Evaluation
2. 2023 FIGO Guidelines -- Revised Staging of Endometrial Cancer
3. ESGO/ESTRO/ESP Guidelines -- Imaging and Surgical Management of EC