On Wednesday 24 June 2020, M.P. van der Meulen will defend her PhD dissertation, entitled: ‘Improving the Performance and Efficiency of the Colorectal Cancer Screening Programme in the Netherlands’.
Colorectal cancer (CRC) is the second-most common cause of cancer mortality in the western world. The incidence in the Netherlands has been steadily rising from 7,100 cases in 1990 to 13,028 in 2013. Colorectal cancer is believed to develop from a precursor lesion, the adenoma, and more recently an alternative pathway to CRC is described, called the sessile serrated polyp pathway. About 30% of adults between the age of 50 and 75 years old has adenomas in their colorectum. Only a small percentage of these adenomas will eventually develop into a CRC.
With screening, if these adenomas are removed, colorectal cancer can be prevented. If an adenoma has developed into CRC, it mostly does not give symptoms right away and is called preclinical CRC. With screening, CRC can be detected in this preclinical stage. Because treatment will then take place at an earlier stage, there is a higher probability of complete resection, a lower probability of side effects and of lymphatic or distant metastasis. Thus, prevention and early detection of CRC can improve the survival and limit the need for harmful treatments. Indeed, several randomized controlled trials have demonstrated a CRC mortality reduction ranging from 15%-33%.
Colorectal cancer screening is therefore widely adopted across the world. However, the screening programs differ in the way they are organized, the choice of screening test and the age range and interval of screening. The different screening tests already used for CRC screening are the guaiac faecal occult blood test (gFOBT), faecal immunochemical test (FIT), colonoscopy, sigmoidoscopy and computed tomography colonography (CTC).
In the Netherlands, pilot-studies were performed to investigate the acceptance and performance of CRC screening with different screening tests (gFOBT, sigmoidoscopy, FIT, CTC and colonoscopy). FIT was observed to have the highest participation rate. Based on these findings, a population-based CRC screening programme using biennial FIT was introduced in the Netherlands in 2014 with a gradual roll-out period of five years.
The PhD defences will not take place publicly in the Senate Hall or Professor Andries Queridoroom due to the coronavirus. The candidates will defend their thesis online.