CEACAM5 and squamous cell carcinoma: The univariate analysis showed that presence of COPD, older age, positive smoking history, smoking index ≥20 pack‐years, ECOG PS ≥2, advanced disease stage (stages III and IV), squamous cell carcinoma histological subtype, nonsurgery initial treatment, the presence of a cough, hemoptysis, neurological symptoms, cardiovascular disease, elevated serum CEA and NLR were predictors for shorter survival times.