Construction and validation of LODDS-based nomogram for prognosis of stageⅠ-Ⅱ gastric signet ring cell carcinoma

Objective To explore the predictive value of log odds of positive lymph nodes（LODDS）for survival outcomes in stage Ⅰ-Ⅱ gastric signet ring cell carcinoma patients，thus constructing and verifying a LODDS-based nomogram. Methods Clinical data of 680 cases from the Surveillance, Epidemiology, and End results （SEER）Program and 62 patients with stage Ⅰ-Ⅱ gastric signet ring cell carcinoma from Yixing People’s Hospital Affiliated to Jiangsu University were retrospectively collected from 2013 to 2017 as the training set and validation set，respectively.The X-tile software was applied to identify best cut off values of LODDS. The Kaplan-Meier method was applied to plot survival curves according to LODDS categories，and the prognostic performance of LODDS was evaluated by receiver operating characteristic（ROC）curve analysis. The Cox regression analysis was used to identify independent risk factors for prognosis of stage Ⅰ-Ⅱ gastric signet ring cell carcinoma patients，which were further used to establish a LODDS-based nomogram. Results LODDS was associated with gender and N stage in training set（P