Routine laboratory tests, tumour markers (CEA, CA 19-9, CGA, 5-hydroxyindoleacetic acid), endoscopic investigation of the gastrointestinal tract, abdominal ultrasound, ultrasound of lymph nodes, chest radiography and CT or whole-body PET/PET-CT scans may be used during follow-up. This evidence concerns the gene CEACAM5 and neoplasm.