The CRS ranges from 0 to 5 points, with 1 point assigned for each of the following: LNM of the primary tumor, the interval < 1 year from primary tumor resection to the detection of liver metastasis, preoperative CEA > 200 ng/ml, more than one liver tumor, and largest tumor > 5 cm [41]. Here, CEACAM5 is linked to neoplasm.