CEACAM5 and metastasis: Except that there were more male patients in the isolated lung metastasis group compared with the SPLC group (p = 0.035), other factors, including age, primary CRC tumor location, initial TNM stage, histological type, treatment of CRC, serum CEA level, serum CA19-9 level, ITP, and OS, were not significantly different among the three groups (p > 0.05; Figure 1).