An alternative option for “resect and discard” strategy, using magnifying narrow-band imaging: a prospective “proof-of-principle” study

Background: The “resect and discard” strategy is beneficial for cost savings on screening and surveillance colonoscopy, but it has the risk to discard lesions with advanced histology or small invasive cancer (small advanced lesion; SALs). The aim of this study was to prove the principle of new “resect and discard” strategy with consideration for SALs using magnifying narrow-band imaging (M-NBI). Methods: Patients undergoing colonoscopy at a tertiary center were involved in this prospective trial. For each detected polyp <10 mm, optical diagnosis (OD) and virtual management (“leave in situ”, “discard” or “send for pathology”) were independently made using non-magnifying NBI (N-NBI) and M-NBI, and next surveillance interval were predicted. Histological and optical diagnosis results of all polyps were compared. Results: While the management could be decided in 82 % of polyps smaller than 10 mm, 24/31 (77 %) SALs including two small invasive cancers were not discarded based on OD using M-NBI. The sensitivity [90 % confidence interval (CI)] of M-NBI for SALs was 0.77 (0.61–0.89). The risk for discarding SALs using N-NBI was significantly higher than that using M-NBI (53 vs. 23 %, p = 0.02). The diagnostic accuracy (95 % CI) of M-NBI in distinguishing neoplastic from non-neoplastic lesions [0.88 (0.86–0.90)] was significantly better than that of N-NBI [0.84 (0.82–0.87)] (p = 0.005). Conclusions: The results of our study indicated that our “resect and discard” strategy using M-NBI could work to reduce the risk for discarding SALs including small invasive cancer (UMIN-CTR, UMIN000003740).