Fig. 4

Kaplan-Meier survival analysis based on differences in patient distribution between AJCC N stage and modified N stage: N_1b—mN_1a vs. mN_1b (A); N_2a—mN_1b vs. mN_2a (B); N_2b—mN_1b vs. mN_2a vs. mN_2b (C); mN_1b—N_1b vs. N_2a(D); mN_2a—N_1b vs. N_2a vs. N_2b (E).