Patients in the pCR and WW groups were similar in terms of age, gender, ECOG performance status, personal or family history of cancer, distance of tumor from the anal verge before nIT, cT stage, cN stage, cTNM stage, maximum diameter of the primary tumor on MRI, serum CEA level before nIT, anal complex invasion, mesorectal fascia invasion (MRF+), extramural vascular invasion (EMVI+), and degree of tissue differentiation (all P > 0.05). This evidence concerns the gene CEACAM5 and cancer.