CEACAM5 and neoplasm: The distance from the inferior margin of the tumor to the anal verge (p = 0.007), cT classification (p < 0.001), levels of pretreatment CEA (p = 0.006), and the interval from the end of radiation to surgery (p = 0.002) were significantly correlated with tumor response in the univariate Chi-square analysis when excluding cN classification, chemotherapeutic regimens, imaging features and the types of surgical procedures (Table 3).