Pre‐nCRT CEA levels were independently associated with a poor pCR rate, reduced pathological tumor regression, reduced tumor downstaging, and decreased OS in several patients with locally advanced rectal cancer.76, 84 Other studies have also shown a correlation between post‐CRT CEA levels and pCR.85 These retrospective studies suggest that low pre‐CRT and post‐CRT CEA levels might be useful in predicting pCR and better patient outcomes. Here, CEACAM5 is linked to rectal cancer.