Prognostic and diagnostic value of node-RADS before and after neoadjuvant therapy in locally advanced gastric cancer.

[PURPOSE] The aim of this study was to evaluate the performance of the Node-RADS scoring system in predicting lymph node metastasis in patients with locally advanced gastric cancer(LAGC) before and after neoadjuvant chemotherapy(NAC), and to determine its prognostic value for overall survival(OS) and disease-free survival(DFS).

[METHODS] Data from 131 patients diagnosed with LAGC who underwent NAC were retrospectively reviewed. All patients had undergone surgical treatment. The Node-RADS score was re-assessed by radiologists based on both pre- and post-NAC CT images. A Node-RADS score of ≥3 was considered positive, and its diagnostic value and prognostic impact were analyzed. Survival analyses were performed using Kaplan-Meier curves and Cox regression analysis.

[RESULTS] In the pre-treatment period, a Node-RADS score ≥3 was significantly associated with overall survival (OS) only in the univariate analysis (HR = 2.20 [95 % CI:1.12-4.34],p = 0.023),with no association observed for DFS. In the post-treatment period, OS was significantly associated in both univariate and multivariate analyses (univariate HR = 1.21, [95 % CI:1.00-1.45], p = 0.049;multivariate HR = 3.60, [95 % CI:1.05-12.3], p = 0.041),while DFS was significant only in the univariate analysis(HR = 1.96 [95 % CI:1.16-3.30], p = 0.012).In terms of diagnostic accuracy, applying a Node-RADS ≥3 threshold achieved an AUC of 0.786, with 86.7 % sensitivity and 53.7 % specificity in the pre-treatment period, whereas in the post-treatment period it yielded an AUC of 0.717, with 41.1 % sensitivity and 97.6 % specificity. A total of 61(46.5 %) patients died, and 68(51.9 %) patients experienced disease recurrence during the follow-up period. Among 131 patients, the median follow-up duration OS was 36.5 months [IQR: 19.5-55.7], and the median DFS was 28.5 months [IQR: 16.2-45.4].

[CONCLUSION] The Node-RADS score, particularly in the post-NAC period, is an effective prognostic tool for predicting residual lymph node metastases and survival in patients with LAGC. These findings suggest that the scoring system may aid in clinical decision-making after treatment.