Optimizing detection and management of familial and hereditary colorectal cancer syndromes

Early recognition of familial and hereditary colorectal cancer (CRC) syndromes is at the core of screening and surveillance strategies for patients and their family members, aiming to prevent morbidity and mortality from CRC. Endoscopy facilitates detection and resection of precursor lesions of CRC: adenomas and serrated polyps. Despite the known benefits of colonoscopy surveillance in patients with familial and hereditary CRC syndromes about 70% to 85% are still unidentified.
In the first part of this thesis we focused on improving the detection of patients with familial and hereditary CRC syndromes. We observed that addition of an online validated family history questionnaire to the existing Dutch fecal immunochemical testing (FIT) based CRC screening program did not improve the diagnostic yield compared to the FIT only strategy. Furthermore only a few individuals with familial and hereditary CRC syndromes were identified. We also explored invitees’ consideration on participating in this new approach and observed that participation was not always based on full knowledge of the possible consequences. The second part of this thesis focused on the relative and absolute CRC risk estimations in patients with a familial CRC risk. In the third part we demonstrated the safety and effectiveness of endoscopic resections of gastric and duodenal adenomas, investigated the adenoma distribution post-colectomy and the potential of Sirolimus as a chemopreventive agent in patients with Familial Adenomatous Polyposis. In the final part we confirmed the importance of key colonoscopy quality indicators to ensure adenoma detection and prevent post-colonoscopy CRC in patients with Lynch syndrome.