CEACAM5 and neoplasm: Age, preoperative serum CEA (≤ 30.0 ng/mL/ > 30.0 ng/mL), differentiation of primary tumor (differentiated/undifferentiated), T classification (T1-3/T4), and the number and maximum diameter of synchronous CRLM differed significantly between the L-OHP (+) and (−) groups in our study.