Several imaging technologies have been developed in order to enable the endoscopists to differentiate neoplastic from non-neoplastic lesions. The real-time prediction of polyps histology is clinically relevant as diminutive polyps represent the majority of polyps detected during colonoscopy and have a very low risk of harboring advanced histology or invasive carcinoma. Thus, an optical diagnosis would allow diminutive polyps to be resected and discarded without pathological assessment or left in place without resection, with an enormous cost-saving potential. Recently, the American Society of Gastrointestinal Endoscopy (ASGE) has set the Preservation and Incorporation of Valuable endoscopic Innovation (PIVI) which defined accuracy threshold to be met, in order to consider a new technology ready to be incorporate into clinical practice. Blue Light Imaging (BLI) is a new chromoendoscopy technology integrated in the latest generation ELUXEOTM 7000 endoscopy platform (Fujifilm Co, Tokyo, Japan), based on the direct (i.e. not filtered) emission of blue light with short wavelength (410nm), that enhances visibility of both microvascular and superficial mucosal pattern. In a recent randomized trial BLI was superior to high-definition white light (HDWL) in the real time characterization of subcentimetric and diminutive colonic polyps. Nevertheless, in this study the paucity of diminutive rectosigmoid polyps analyzed does not allow to draw definite conclusions as the meeting of PIVI thresholds are concerned. Similarly, the low numbers of patients evaluated limited the per-patient analysis. Therefore further studies adequately powered to this clinically end-point were advocated. Additionally, when the study was performed a BLI dedicated classification for optical diagnosis of colonic polyps was not available, whereas recently a specific classification (the BLI Adenoma Serrated International Classification-BASIC) has been developed and a specific training set has been settled.

In the present study the investigators prospectively evaluate whether the use of BLI-assisted optical characterization of diminutive polyps using BASIC classification by specifically trained endoscopists may met PIVI thresholds and particularly if it allow the endoscopists to achieve > 90% correct assignment of post-polypectomy surveillance intervals when combined with the histopathology assessment of polyps >5 mm in size.

Inclusion Criteria:

• Consecutive adult (18-80 yrs) outpatients undergoing colonoscopy in the frame of the FOBT based screening program or for CRC primary prevention, in which at least one diminutive (<5 mm) rectosigmoid polyp is detected.

Exclusion Criteria:

• patients with CRC history or hereditary polyposis syndromes or hereditary non-polyposis colorectal cancer
• patients with inadequate bowel preparation
• patients in which caecal intubation was not achieved or scheduled for partial examinations
• polyps could not be resected due to ongoing anticoagulation preventing resection and pathologic assessment

Consecutive adult (18-80 yrs) outpatients undergoing colonoscopy in the frame of the FOBT based screening program or for CRC primary prevention, in which at least one diminutive (<5 mm) rectosigmoid polyp is detected.