CEACAM5 and neoplasm: 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.