CEACAM5 and neoplasm: There were significant differences in the frequency of liver metastasis, resection of the primary tumor, and sum of the tumor diameters between the ctDNA‐positive/CEA‐negative cases and concordant cases (liver metastasis, p = 0.02; resection of primary tumor, p = 0.006; tumor diameter, p < 0.0001; Table 3).