CT-based Node-RADS classification in the assessment of rectal cancer: diagnostic performance and postoperative prognostic stratification
摘要
Lymph node metastasis significantly impacts rectal cancer prognosis and treatment planning; yet, current imaging assessment methods lack standardization. This study aimed to evaluate the diagnostic performance and postoperative prognostic implications of the Node Reporting and Data System (Node-RADS) 1.0 categories in the initial regional nodal assessment of rectal cancer.
MethodsThis retrospective study included 188 consecutive patients with rectal cancer without preoperative treatment who underwent surgery between 2017 and 2024. Two radiologists evaluated regional lymph nodes according to the Node-RADS 1.0 criteria and assigned each patient the highest Node-RADS category on the basis of computed tomography (CT) images. Survival and recurrence data were retrospectively collected. Interobserver agreement was assessed by weighted kappa statistics. Diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis. The Kaplan‒Meier method, log-rank test, and Cox regression were used to evaluate overall survival (OS) and recurrence-free survival (RFS). Subgroup analyses were performed according to the adjuvant therapy status.
ResultsNode-RADS yielded an area under the curve (AUC) of 0.847, a sensitivity of 71.9% and a specificity of 93.5%. Substantial interobserver agreement was observed in the Node-RADS categories assigned by the two readers (weighted κ = 0.748, 95% CI: 0.692–0.805). On the basis of the optimal cutoff value, patients were divided into low-risk Node-RADS (categories 1–3) and high-risk Node-RADS (categories 4–5) groups. During a median follow-up of 52.1 months, patients with Node-RADS categories 4–5 demonstrated poorer OS and RFS than did those with lower Node-RADS categories (both p < 0.001), and this survival difference remained significant in subgroups, regardless of the postoperative adjuvant therapy status (all p < 0.05). In the multivariable analysis, Node-RADS category 4–5 was significantly associated with both poor OS (hazard ratio [HR] = 2.58, 95% CI: 1.21–5.49, p = 0.014) and poor RFS (HR = 2.99, 95% CI: 1.35–6.61, p = 0.007).
ConclusionsThe Node-RADS category during the primary staging of rectal cancer was a significant predictor of postsurgical patient outcomes, but prospective and multicentre validation is needed to confirm its clinical utility. Our findings suggest that CECT-based Node-RADS could serve as a valuable tool for risk stratification and treatment planning for patients with rectal cancer.
Trial registrationThis was a retrospective study and did not require clinical trial registration.