The FIT for Follow-Up study aimed to find out whether annual Faecal Immunochemical Tests (FIT), which detect traces of blood in stool, are accurate enough to replace three-yearly colonoscopy (an examination of the inside of the bowel) in people who have previously had a large polyp, or a few small polyps, removed at colonoscopy. FITs are quicker, cheaper and easier than colonoscopy, which has risks of complications.
A total of 8009 people were invited to participate in the study. Of those invited, 5938 (74%) returned a signed consent form and completed a FIT at year one; these individuals were included in our study. Participation in the study was similar amongst men and women, and across age groups.
We found that FIT was well-accepted with 97% of participants returning FIT kits at years 2 and 3. Over the three years of the study, 786 (13%) participants tested FIT positive and, therefore, required a colonoscopy earlier than usually scheduled.
Unless they had a colonoscopy early as a result of a positive FIT, all participants were invited to have a colonoscopy at the end of the study (after 3 years). Of the 5938 participants in the study, 5225 had a colonoscopy at some time during the study. During the three years, bowel cancer was diagnosed in 29 participants and advanced adenomas were diagnosed in 446.
In total, 725 (12%) participants underwent a colonoscopy as a result of a positive FIT result. Amongst these individuals, cancer was found in 17 and advanced adenomas in 151. FIT therefore identified 17 of 29 (59%) participants with cancer and 151 of 446 (34%) participants with advanced adenomas.
Overall, the study demonstrated that annual FIT could identify 59 of every 100 cancers and 34 of every 100 patients with advanced adenomas if repeated over three years. To our knowledge, this study is the only one to have evaluated FIT for monitoring people who have previously had a large polyp, or a few small polyps, removed at colonoscopy.
The results of the FIT for Follow-Up study have recently been published on the NHS National Institute for Health Research website and in the journal GUT. The results were also presented to an audience of clinicians, gastroenterologists and research scientists at the British Society of Gastroenterology Annual Meeting in Liverpool, UK in June 2018.