CEACAM5 and colorectal carcinoma: For instance, while the NICE UK recommends scheduled bi-annual serum carcinoembryonic antigen (CEA) testing, yearly computed tomography scans (CT scans) of the thorax and abdomen, and colonoscopy done at the first and third year after primary surgery done with curative intent [133], stage I CRC has significantly lower reoccurrence rates of less than 10% [134] as opposed to more advanced CRC stages, which may reoccur in about 40% of patients after initial surgery and may need more intensive follow-up [135,136].