A nomogram for predicting individual survival of patients with gastric cancer who underwent radical surgery with extended lymph node dissection

Background: We developed and validated a nomogram for use at a high-volume center where radical surgery with extended lymph node dissection is the standard treatment for gastric cancer. Methods: Overall, 1,614 patients were randomly divided into the test set (n = 805) and validation set (n = 809). The scoring system was calculated using a Cox proportional hazard regression model with the survival of gastric cancer as the predicted endpoint. The concordance index (c-index) was used as an accuracy measure, with bootstrapping to correct for optimistic bias. Calibration plots were constructed. Results: Based on a Cox model, we developed a nomogram that predicts the probability of 3- and 5-year survival from the time of surgery. The bootstrap-corrected c-indices were 0.87 and 0.84 in the test and validation sets, respectively. Survival was well predicted in both sets. The predictions of our nomogram discriminated better than the AJCC staging system (test set: c-index, 0.87 vs. 0.77; P < 0.0001; validation set: c-index, 0.84 vs. 0.79; P < 0.001). Conclusion: We developed and validated a nomogram that provided a significantly accurate prediction of postoperative survival in Korean patients with gastric cancer who underwent radical gastrectomy with extended lymph node dissection.