Establishment and validation of a prognostic model for gastric signet ring cell carcinoma based on positive lymph node ratio

Objective To investigate the prognostic value of positive lymph node ratio (LNR) in gastric signet ring cell carcinoma (GSRCC) and to construct a LNR-based prognostic nomogram for validation. Methods Data from GSRCC patients in the SEER database and Yixing Hospital Affiliated to Jiangsu University were collected and categorized as training and validation sets, respectively. Kaplan-Meier method was used to plot survival curves, and univariate and multivariate Cox models were applied for prognostic analysis. A LNR-based prognostic nomogram was constructed and validated using the validation set. Results Compared with patients with a low LNR, those with a high LNR had a more advanced tumor stage, and patients with a medium LNR had a higher proportion of chemotherapy (P<0.05). In the training set, the 5-year cancer-specific survival (CSS) rates for the low, medium, and high LNR groups were 71.1%, 30.7%, and 8.9%, respectively, with statistical differences (P<0.05). In the validation set, the 5-year CSS rates for the low, medium, and high LNR groups were 85.0%, 53.2%, and 17.9%, respectively, with statistical differences (P<0.05). Multivariate regression analysis showed that age, tumor size, T stage, LNR, overall Stage, and chemotherapy were independent prognostic factors for GSRCC. Furthermore, a nomogram model was constructed, demonstrating good predictive consistency in both internal and external validation. In internal validation, the area under the curve (AUC) for 1-, 3-, and 5-year survival rates were 0.787, 0.848, and 0.855, respectively. In external validation, the corresponding AUC values were 0.724, 0.729, and 0.737. Conclusions LNR has independent prognostic value in GSRCC patients. The LNR-based nomogram model can be considered an important prognostic indicator for GSRCC.