Implementation of optical diagnosis with a “resect and discard” strategy in clinical practice: DISCARD3 study

      Background and Aims

      Optical diagnosis (OD) of polyps can be performed with advanced endoscopic imaging. For high-confidence diagnoses, a “resect and discard” strategy could offer significant histopathology time and cost savings. The implementation threshold is a ≥90% OD-histology surveillance interval concordance. Here we assessed the OD learning curve and feasibility of a resect and discard strategy for ≤5-mm and <10-mm polyps in a bowel cancer screening setting.


      In this prospective feasibility study, 8 bowel cancer screening endoscopists completed a validated OD training module and performed procedures. All <10-mm consecutive polyps had white-light and narrow-band images taken and were given high- or low-confidence diagnoses until 120 high-confidence ≤5-mm polyp diagnoses had been performed. All polyps had standard histology. High-confidence OD errors underwent root-cause analysis. Histology and OD-derived surveillance intervals were calculated.


      Of 565 invited patients, 525 patients were included. A total of 1560 <10-mm polyps underwent OD and were resected and retrieved (1329 ≤5 mm and 231 6-9 mm). There were no <10-mm polyp cancers. High-confidence OD was accurate in 81.5% of ≤5-mm and 92.8% of 6-9-mm polyps. Sensitivity for OD of a ≤5-mm adenoma was 93.0% with a positive predictive value of 90.8%. OD-histology surveillance interval concordance for ≤5-mm OD was 91.3% (209/229) for U.S. Multi-Society Task Force, 98.3% (225/229) for European Society of Gastrointestinal Endoscopy, and 98.7% (226/229) for British Society of Gastroenterology guidelines, respectively.


      A resect and discard strategy for high-confidence ≤5-mm polyp OD in a group of bowel cancer screening colonoscopists is feasible and safe, with performance exceeding the 90% surveillance interval concordance required for implementation in clinical practice. (Clinical trial registration number: NCT04710693.)


      BCSP (bowel cancer screening program), BSG (British Society of Gastroenterology), DISCARD (Detect InSpect ChAracterise Resect and Discard), ESGE (European Society of Gastrointestinal Endoscopy), NBI (narrow-band imaging), NICE (NBI International Colorectal Endoscopic), OD (optical diagnosis), PIVI (Preservation and Incorporation of Valuable Endoscopic Innovations)
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      Linked Article

      • It’s not lack of evidence holding back resect and discard
        Gastrointestinal EndoscopyVol. 96Issue 6
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          Optical diagnosis (OD) refers to histology prediction based on endoscopic features. OD has several potential uses in colonoscopy (Table 1). The most transformative potential use of OD in colonoscopy is to alter the management of diminutive colorectal polyps. In 2011, the American Society for Gastrointestinal Endoscopy (ASGE) proposed 2 practice strategies using OD to reduce risk and/or cost associated with endoscopic resection of diminutive polyps, accompanied by minimum OD performance thresholds at which the strategies would be accepted for implementation.
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