CEACAM5 and adenocarcinoma: In the univariate analysis, many factors were significantly associated with poor OS, including older age, male sex, poor performance status (ECOG ≥ 1), smoking status, higher preoperative CEA levels (≥ 5 ng/mL), extensive resection, thoracotomy, non-adenocarcinoma histology, poorly differentiated tumors, VPI, LVI, positive resection margins, more advanced stage (stage II–IV), and type of primary malignancy other than breast or thyroid cancer.