According to age (≥ 65 vs. < 65 years), gender (male and female), tumor stage (stage 3–4: advanced-stage and stage 1–2: early-stage), KRAS mutation status (positive and negative), TP53 mutation status (positive and negative), and EGFR mutation status (positive and negative) in the entire data (Figs. 3 and 4), we performed stratification analyses. Here, EGFR is linked to neoplasm.