More people than expected participated in the first year of the population screening for bowel cancer, which was found in 2,500 people. This was established in a study undertaken for RIVM by Erasmus Medical Centre and Antoni van Leeuwenhoek Hospital, which analysed data on 741,914 participants. The unexpectedly high participation has put pressure on colonoscopy capacity in some areas.

The percentage of people participating in the population screening was 71.3% (529,056 people), which was higher than in the first half of 2014 (68%) and considerably higher than in the trial population screening (60%). As a result, capacity in some areas is not sufficient to meet the need for follow-up investigations, which means that some people will be invited later than planned.

When the cut-off value for the stools test was adjusted, the number of colonoscopy referrals decreased by 6.3%, in line with the prognosis based on previous screenings. Colonoscopy is an endoscopic examination of the large bowel. Of the 31,759 people who had a colonoscopy, 2,483 people (7.8%) were found to have colorectal cancer and 12,030 (37.9%) to have polyps. As some polyps can become cancerous, their removal can prevent the development of bowel cancer. Except for the higher level of participation, these data are largely in line with the prognosis based on previous studies.

Phased implementation

Population screening is being phased to ensure sufficient time to build the necessary capacity to carry out the follow-up investigations. Those with an unfavourable stool test are invited for an intake interview and a colonoscopy in a hospital or endoscopy centre. The aim is to reduce the waiting time for the follow-up investigation as much as possible so that participants get certainty as quickly as possible about the implications of the first investigation.

Fewer deaths

Bowel cancer is often called a silent killer because it takes a long time to develop and to produce symptoms, and for a patient with symptoms to consult a doctor. Population screening can detect bowel cancer in an early stage, and these people can be seen earlier by a gastroenterologist. Early identification of bowel cancer means that treatment is often less severe and there are more treatment options. Bowel cancer can be prevented by the removal of polyps, which are potentially an early stage of cancer. Population screening will contribute to fewer deaths from this disease.