In the present study, stage‐specific RFS and OS rates in patients with stage III rectal cancer, but not stage I or II rectal cancer, differed significantly by group, similar to the previous report.9 One possible reason for this is the inclusion of patients with falsely elevated CEA in stage I/II, due to the reference range of CEA ≤ 5 ng/ml used in the present study. Here, CEACAM5 is linked to rectal cancer.