Fig. 1From: Modified nodal stage of esophageal cancer based on the evaluation of the hazard rate of the negative and positive lymph nodeThe comparison of overall survival between training group and validation group. a The survival difference among N1, N2 and N3 sub group in training data were significant(P < 0.05). b The survival difference among N1, N2 and N3 sub group in validation data were significant(P < 0.05)Back to article page