Figure 2

Kaplan–Meier curves. (a) Kaplan–Meier curves according to the TNM (8th UICC/AJCC) classification system. (b) Kaplan–Meier curves according to the mTNM-NR classification system. UICC union of international cancer control, AJCC American joint committee on cancer, NR lymph node metastatic ratio, mTNM-NR modified TNM stage using NR.