For example, if a SCLC patient that was a male, combined with T2N2, ECOG ≥2, HGB <115 g/L, LYMPH # <1.1 × 109/L, PLT <125 × 109/L, RBP >70 mg/L, CEA >10 ng/mL and NSE >16.3 ng/mL, was defined to be 0.839 (95% CI: 0.250–0.988), which was higher than the risk score, and the patients were classified to the high‐risk group. Here, CEACAM5 is linked to small cell lung carcinoma.