External Validation of a Nomogram Developed for Predicting Overall Survival in Gastric Cancer Patients with Insufficient Number of Examined Lymph Nodes.

Objectives: Nomograms and scoring systems in gastric cancers have been mainly developed based on adequate lymph node (lN) dissections. This study aimed to perform external validation of a nomogram developed for predicting overall survival (OS) in gastric cancer patients with insufficient number of examined LNs (eLNs) and to evaluate its usability as compared with the 8 Methods: Medical records of 262 patients undergoing complete surgical resection for gastric cancers and having pathologically confirmed diagnosis were retrospectively reviewed. The study included 104 (39.7%) patients (82 males, median age, 60.3 years) with insufficient number of eLNs (<16). The 5-year OS rate was calculated using the nomogram and according to the AJCC system. Results: The median follow-up period was 37.4 months (range: 0.9-122.9). Of the patients, 69 (66.3%) died and 35 (33.7%) achieved 5-year survival within the follow-up period. The nomogram and the AJCC system predicted OS were significantly lower in patients who died than in those who achieved 5-year survival (p<0.001 for both). According to the receiver operative characteristics-curve, the area under the curve for the nomogram (0.801; 95% CI, 0.715-0.887; p<0.001) was larger than that for the AJCC system (0.754; 95% CI, 0.659-0.849; p<0.001). Conclusion: The nomogram developed for gastric cancer patients with insufficient number of eLNs (<16) was effective in predicting 5-year OS in our cohort and was superior to the AJCC system.