The FACS (Follow-up after Colorectal Surgery) trail was a multicentre trial that randomized 1202 patients treated for Dukes’ stage A–C cancer to minimum follow-up (CT CAP at 12 to 18 months if requested at study entry by the treating clinician) or one of three other higher intensity groups that included CEA and CT CAP combined (CEA every 3 months for 2 years, and then every 6 months for 3 years; CT CAP every 6 months for 2 years, and then annually for 3 years), CEA alone, or CT CAP alone. The gene discussed is CEACAM5; the disease is cancer.