CT-based Node-RADS for standardized evaluation of lymph node metastasis in rectal cancer and its clinicopathological correlates.
Abstract
Background
Lymph node metastasis identification has important clinical implications for treatment decision-making in rectal cancer (RC). To evaluate the diagnostic performance of the CT-based Node Reporting and Data System 1.0 (Node-RADS) for lymph node metastasis risk in treatment-naive RC patients, and to investigate the correlation between the Node-RADS score and clinicopathological factors.
Methods
A single-center retrospective study was performed to RC patients (Aug 2020-Dec 2025) who underwent radical resection surgery and preoperative contrast-enhanced CT examination. Lymph node status was assessed using Node-RADS score ranging from 1 to 5. Sensitivity, specificity, and Youden's index were calculated for different Node-RADS cut-off values. The overall diagnostic performance was evaluated using receiver operating characteristic curves and the area under the curve (AUC). The associations between Node-RADS score and clinicopathological parameters were analyzed.
Results
A total of 459 RC patients were evaluated, including 174 pN + and 285 pN-. Node-RADS scores ≥ 3 and ≥ 4 have the satisfactory diagnostic performance, with sensitivity/ specificity/Youden's index of 87.36 %/58.25 %/0.46 for Node-RADS scores ≥ 3 by Reader 1, 89.08 %/54.04 %/0.43 for Node-RADS scores ≥ 3 by Reader 2, 74.14 %/78.95 %/0.53 for Node-RADS scores ≥ 4 by Reader 1, and 72.99 %/75.44 %/0.48 for Node-RADS scores ≥ 4 by Reader 2, respectively. The AUC of Node-RADS scores were 0.831(95 %CI:0.793-0.864) and 0.806(95 %CI:0.767-0.841) by Reader 1 and Reader 2, respectively. Node-RADS score correlated with pathological T stage, N stage, and lymphovascular invasion. The inter-reader agreement for Node-RADS score were substantial, with weighted kappa values of 0.650.
Conclusions
The CT-based Node-RADS demonstrates stability and satisfactory diagnostic performance for identifying patients with lymph node metastasis in treatment-naive RC.