CEACAM5 and malignant colon neoplasm: Furthermore, PSM was used to consolidated our finding, and analyses after PSM once again demonstrated ACT did not substantially improve survival in stage IIA colon cancer with elevated serum CEA levels and elevated serum CEA should not be used as one of high-risk factors to guide ACT, which was consistent with the ASCO and ESMO recommendations (6, 7) and added a strong evidence to the view of the ASCO Tumor Marker Panel that there was not sufficient data to support the use of preoperative CEA levels to guide the receipt of ACT stage II tumor (8).