Considering the results of the multivariate analysis, patients were categorized into 3 subgroups based on whether the patients had a serum CEA ≥ 5.0 ng/mL before lung metastasectomy and a DFI < 24 months after CRC resection, which are 2 unfavorable factors for OS (Fig. 2a). Here, CEACAM5 is linked to colorectal carcinoma.