CEACAM5 and metastatic neoplasm: The CRS is based on five easy‐to‐obtain clinical indicators: disease‐free interval less than 12 months, preoperative carcinoembryonic antigen (CEA) level >200 ng/mL, largest hepatic metastatic tumor size >5 cm, node‐positive primary, and number of hepatic metastatic tumors >1.