CEACAM5 and rectal cancer: A study of 531 locally advanced rectal cancer patients with NCRT by Yang et al. [11] revealed that CEA ≤ 5 ng/mL before neoadjuvant therapy was associated with pCR (p = 0.021), and a low level of CEA before NCRT was a predictor of pCR (OR = 0.435, 95 m2 CIx: 0.214–1.010, P = 0.03).