CEACAM5 and neoplasm: In multivariate logistic regression analysis, low CEA level after NCRT was an independent predictor of pCR (OR = 1.74, 95% CI: 1.06–3.81); Saito et al. [26] revealed that serum CEA level after NCRT was lower than 5 ng/mL for patients with higher tumor shrinkage rates than those with serum CEA levels ≥ 5 ng/mL.