PhD defence S.A.V. (Stella) Nieuwenburg

Dissertation in short:

This thesis aims to optimise prevention programmes for gastric- and colorectal cancer.

The first part consists of studies on surveillance of premalignant gastric lesions. Prospectively, we evaluated current guidelines on the proper identification of patients with premalignant gastric lesions that deserve further follow up. After one extra gastro endoscopy – were guidelines would advise to stop further surveillance - it appeared that a considerable part would have an indication for further surveillance after all. We investigated several possibilities for the improvement of surveillance programmes. To name; the use of a new endoscopy technique, evaluating risk factors within patients (such as smoking and a family history of gastric cancer), and the new possibility of detecting the most important risk factor for the occurrence of gastric cancer – Helicobacter Pylori bacterium – in the fecal test used in colorectal cancer screening.  

The second part of this thesis consist of studies on colorectal cancer screening. First, the video capsule was used to determine prevalence rates of several abnormalities (benign or malignant) in a general population. Further, a comprehensive retrospective study in 20 European countries was performed on the incidence of colorectal cancer over time within different age groups. This showed that the incidence is increasing mostly at younger ages. Lastly, literature studies were performed in order to further improve and innovate the current colorectal cancer screening programme. We showed that the use of anticoagulants do not affect the fecal blood test used in screening. Also, the video capsule appeared to be a good alternative beside colonoscopy.