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The learning curve for detection of non-polypoid (flat and depressed) colorectal neoplasms
  1. Sarah K McGill1,2,
  2. Tonya Kaltenbach1,2,
  3. Shai Friedland1,2,
  4. Roy Soetikno1,2
  1. 1Gastrointestinal Endoscopy Unit, Veterans Affairs Palo Alto Heath Care System, Palo Alto, California, USA
  2. 2Department of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, USA
  1. Correspondence to Dr Roy Soetikno, Department of Gastroenterology and Hepatology, Veterans Affairs Palo Alto, 3801 Miranda ave, Palo Alto, CA 94304, USA and Department of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA; soetikno{at}

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We read with interest the two excellent studies on interval colorectal cancers (CRC) following colonoscopy and wish to present important data relevant to the prevention of interval CRC. In a pooled multicohort analysis, Robertson and coauthors found that invasive cancer was diagnosed in 0.6% of patients after clearing colonoscopy among eight large North American trials, and concluded that half of these were likely missed lesions.1 In a population-based study, le Clercq and coauthors reported that CRC found following colonoscopy were more likely to have non-polypoid morphology than prevalent cancers.2

We previously described that non-polypoid colorectal neoplasms (NP-CRN) harbour more advanced pathology than polypoid neoplasms.3 Indeed, due to their subtle appearance, NP-CRN may be a key contributor to interval CRC. The learning curve in their detection is largely unknown.

Using available data, we summarised the learning curve (see figure 1) for the detection …

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  • Correction notice This article has been corrected since it was published Online First. The author name Sarah McGill has been amended to read Sarah K McGill.

  • Contributors SM, TK, RS contributed to the study's concept and design. SM, TK and SF analysed the data. SM drafted the manuscript, which was revised by all coauthors. All authors accepted the final version of the manuscript. RS is guarantor.

  • Competing interests None.

  • Ethics approval Stanford University and Veterans Affairs Palo Alto Health Care System.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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