I just don’t think I have cancer Why some participants do not follow up with a recommended colonoscopy in colorectal cancer screening

Participants who receive an unfavourable screening result in two-step colorectal cancer screening programmes have a significantly increased risk of colorectal cancer. They are therefore recommended a colonoscopy to examine the colon for the presence of cancer or a precursor to cancer. However, non-follow up of colonoscopy is an issue in almost all invitation based colorectal cancer-screening programmes. This thesis aimed to find out why some participants in the Dutch colorectal cancer-screening programme do not undergo colonoscopy after an unfavourable screening result. Methods used were interviews and a nation-wide questionnaire.
Results showed that participants who did not undergo colonoscopy more often feel their risk for colorectal cancer is low; more often have difficulties deciding, and have lower knowledge levels than those who do undergo colonoscopy. A negative colonoscopy advice from someone outside of the medical setting as well as referral to an unfamiliar colonoscopy location were also associated with non-follow up. Participants who do undergo colonoscopy more often believe their general practitioner is supportive of this examination. One third of participants who underwent the recommended colonoscopy (with a favourable outcome) reported high levels of cancer worry.
This thesis theorizes that participation in two-step cancer screening may be viewed as a two-step decision by invitees, and that feelings of moral obligation may lead to participation that is less informed than prescribed by the rational choice model. As such, placing emphasis on colorectal cancer screening participation as a 1-step decision and offering guidance to those with decisional difficulties may offer opportunities for further improvement of population based colorectal cancer screening.