Real-time diminutive (≤5 mm) colonic polyp characterization by virtual blue-light (i.e.
Narrow Banding Imaging [NBI], Blue Light Imaging [BLI], etc.) has been identified as a
key goal for novel endoscopic advanced imaging techniques. The real-time prediction of
polyps histology, especially of those located in the rectosigmoid, is clinically relevant
as diminutive polyps represent the majority of polyps detected during colonoscopy and
have a very low risk of harboring advanced histology (0.3%) and a negligible risk of
invasive carcinoma (0%-0.08%).
Thus, as recommended by current guidelines, an optical diagnosis would allow diminutive
polyps to be resected and discarded without pathological assessment (i.e.
resect-and-discard strategy) or left in place without resection in the case of diminutive
rectosigmoid hyperplastic polyps (i.e. leave-in-situ strategy), with an enormous
cost-saving potential. In addition, the current policy for managing such
hyperplastic-appearing polyps is poorly defined and variable from endoscopist to
endoscopist. For instance, the European Society of Gastrointestinal Endoscopy (ESGE)
recommends to leave-in-situ only diminutive polyps characterized as hyperplastic with
high-confidence. However, it is currently unknown how many endoscopists actually do
switch to the blue-light advanced imaging (when available) that is required for a
high-confident diagnosis when assessing ≤5 mm hyperplastic-appearing lesions. More
importantly, the Leave-in-situ strategy, poorly defined in a pre-AI era, has never been
clinically validated, leaving uncertainty on the estimate of the possible false negatives
generated by an inaccurate diagnosis6.
The availability of Computer-Aided-Diagnosis (CADx) tools, which may help endoscopists
distinguish neoplastic from non-neoplastic polyps making the characterization process
quicker and more objective, would be highly desirable and captivating.
A new system for CADx during white light endoscopy has been developed and integrated
alongside a previously available Computer-Aided-Detection (CADe) tool (GI-Genius,
Medtronic), making real-time characterization straightforward after polyp detection, and
has been recently validated in a real time clinical trial, showing how this system
exceeds the American Society of Gastrointestinal Endoscopy (ASGE) Criteria for clinical
application of cost saving strategies (i.e. leave in situ and resect and discard), and
equals the performance of expert endoscopists in optical diagnosis. However, this was a
first study, monocentric and without randomization, with a small, albeit adequately
powered, sample size. The need for larger trials is thus urgent to speed up the possible
implementation of CADx in clinical practice.
Aim of this study is to clinically validate the new CADx tool for the implementation of a
leave-in-situ strategy in a multicenter, randomized controlled trial.