Bowel cancer is the third most common cancer in the UK. It develops through smaller growths in the bowel called polyps. Early recognition and removal of these polyps result in prevention of developing bowel cancer in an individual. However, not all polyps will lead to cancer, certain polyps are just growths of normal tissue and can be left in the bowel. We therefore need to know which polyps to remove and which ones to leave. One way of doing this is to have a better look at these polyps. This can be done by new technologies. One of them is called Blue Light Imaging (BLI). This is a new light source at the end of the camera which is activated by the push of a button. It will help us in looking at these polyps more closely.

This helps us decide which polyps to remove and which ones are safe to leave as there is always a small risk in removing a polyp. It would also give us a better idea as to when to repeat the camera test if necessary (endoscopic surveillance). By reducing the number of polyps resected and sent to the pathology labs for diagnosis, the work load on the pathology department is also reduced and in the process, providing cost savings to the Trust, The study aims to see if using Blue Light during endoscopy helps us to identify and characterize small polyps better

Advanced endoscopic imaging can facilitate the characterisation of neoplastic and non-neoplastic polyps. Accurate identification of small non-neoplastic polyps (e.g. rectosigmoid hyperplastic polyps) that do not harbour malignant potential can lead to future implementation of a 'resect and discard' or 'diagnose and leave' strategy. However, there is insufficient evidence that endoscopists are able to attain high enough levels of optical diagnostic performance in-vivo in order to implement this strategy safely. Blue Light Imaging (BLI) is a new enhanced imaging technology that enhances mucosal surface and vessel patterns. A specific BLI classification was recently developed to enable better characterisation of colorectal polyps (BLI Adenoma Serrated International Classification - BASIC). The use of this technology with the appropriate classification to enhance its performance has not yet been tested in clinical settings of polyp surveillance and screening colonoscopy amongst general endoscopists.

BLAST is a multicentre prospective observational study which will compare BLI optical diagnosis with histological assessment (as a reference standard) for patients with small polyps (<10mm) identified at colonoscopy.

Inclusion Criteria:

• > 18 years of age Able to provide informed consent

Exclusion Criteria:

• History of polyposis syndrome History of Inflammatory bowel disease History of poor bowel prep

All patients undergoing colonoscopy who fulfill eligibility criteria.

Anonymised data regarding ensdoscopic findings and histological diagnosis might be shared with other researchers if the need arises.