Fig. 3

a, b Validity of the predictive performance of the nomogram in estimating the risk of lymph node metastasis in early gastric cancer patients. a Internal calibration curve to validate the nomogram model and the C-index was 0.82 (95%CI, 0.78 to 0.80). b External calibration curve to validate the nomogram model and the C-index was 0.77 (95%CI, 0.60 to 0.94)