Résumé : Identifying new prognostic factors is important for guiding treatments and preventing metastasis in cancer. Vagal nerve activity may predict prognosis in cancer due to its roles in modulating inflammation, sympathetic activity and oxidative stress. This study tested the relationship between heart rate variability (HRV), a vagal nerve index, and the colon cancer (CC) marker carcinoembryonic antigen (CEA), in an 'historical prospective' design.