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Real-time optical diagnosis for diminutive colorectal polyps using narrow-band imaging: the VALID randomised clinical trial
  1. Tonya Kaltenbach1,
  2. Amit Rastogi2,
  3. Robert V Rouse3,
  4. Kenneth R McQuaid4,
  5. Tohru Sato1,
  6. Ajay Bansal2,
  7. Jon C Kosek3,
  8. Roy Soetikno1
  1. 1Veterans Affairs Palo Alto, GI Endoscopy Unit and Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Palo Alto, California, USA
  2. 2Veterans Affairs Kansas City, Gastroenterology Section and Department of Medicine, Division of Gastroenterology, University of Kansas, Kansas City, Missouri, USA
  3. 3Veterans Affairs Palo Alto, Pathology and Laboratory Medicine Service and Department of Pathology, Stanford University School of Medicine, Palo Alto, California, USA
  4. 4Veterans Affairs San Francisco, Gastrointestinal Diagnostic Unit and Division of Gastroenterology, University California San Francisco, San Francisco, California, USA
  1. Correspondence to Dr Tonya Kaltenbach, Veterans Affairs Palo Alto, Stanford University School of Medicine, Palo Alto, CA 94304, USA; endoresection{at} or tonya.kaltenbach{at}


Background Diminutive (≤5 mm) colorectal polyps are common, and overwhelmingly benign. Routinely, after polypectomy, they are examined pathologically to determine the surveillance intervals. Advances in equipment and techniques, such as narrow-band imaging (NBI) colonoscopy, now permit reliable real-time optical diagnosis.

Methods We conducted a randomised single-masked study involving three institutions to determine whether optical diagnosis of diminutive colorectal polyps meets clinical practice standards and reduces the need for histopathology. We randomly assigned eligible patients undergoing routine high-definition colonoscopy to optical diagnosis using near focus versus standard view, using computer-generated block sequence. By validated criteria, we rendered an optical diagnosis and a confidence level (high vs low) for all polyps, using NBI. Our primary endpoint was the number of accurate high-confidence optical diagnoses compared with central blinded pathology in the two groups. We analysed data using intention to treat.

Findings We enrolled 558 subjects, and randomly assigned 281 to near focus and 277 to standard view optical diagnosis. We detected 1309 predominantly diminutive (74.5%) and neoplastic (60.0%) polyps. Endoscopists were significantly more likely, OR 2.2 (95% CI 1.6 to 3.0, p<0.0001), to make a high-confidence optical diagnosis with near focus (85.1%) than standard (72.6%) view. High-confidence diagnoses had 96.4% and 92.0% negative predictive value, respectively. Of all polyps, 75.3% (95% CI71.3% to 78.9%) had a high-confidence accurate prediction using near focus, compared with 63.1% (95% CI 58.5% to 67.6%) using standard view. Optical versus histopathological diagnosis showed excellent agreement between the surveillance intervals, 93.5% in near focus and 92.2% in standard view. The median diagnosis time was 14 s.

Conclusions Real-time optical diagnosis using NBI colonoscopy may replace the pathology diagnosis for the majority of diminutive colorectal polyps. Using colonoscopy with near focus view increases the confidence level of the optical diagnosis. Optical diagnosis would be a paradigm shift in clinical practice of colonoscopy for colorectal cancer screening.

Trial registration number Identifier: NCT01288833.


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