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Accuracy of measuring colorectal polyp size in pathology: a prospective study
  1. Roupen Djinbachian1,2,
  2. Abdelhakim Khellaf3,
  3. Brandon Noyon2,
  4. Geneviève Soucy3,
  5. Bich N Nguyen3,
  6. Daniel von Renteln1,2
  1. 1 Gastroenterology, Montreal University Hospital Center (CHUM), Montreal, Quebec, Canada
  2. 2 Gastroenterology, Montreal University Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
  3. 3 Pathology, Montreal University Hospital Center (CHUM), Montreal, Quebec, Canada
  1. Correspondence to Dr Daniel von Renteln, University of Montreal Hospital Centre, Montreal, Quebec, H2X 0A9, Canada; danielrenteln{at}

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Guideline-conforming endoscopic polyp resection and follow-up are dependent on accurate polyp sizing estimation. However, studies evaluating the feasibility and accuracy of pathology-based polyp size measurement are lacking. We conducted a prospective clinical study (482 polyps resected in 203 consecutive patients) evaluating pathology-based size measurement for colorectal polyps. To obtain reference size measurements, we measured polyp size immediately after removing polyps from the colon prior to formalin fixation. Due to piecemeal resection or fragmentation of specimens during the retrieval process, only 59% of resected polyps could actually be evaluated histologically for size. The estimated mean polyp shrinkage because of formalin fixation was 26% which resulted in 33% of polyps ≥10 mm pre-fixation being miscategorised as <10 mm post-fixation, and 33% of polyps ≥5 mm pre-fixation being miscategorised as <5 mm post-fixation. Compared with reference size, relative accuracy for measuring polyp size during colonoscopies using a laser-based virtual scale endoscope (VSE) was significantly higher than histological polyp size measurements (84.2% vs 74.1%, p<0.0001).

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The European Society of Gastrointestinal Endoscopy (ESGE) recommends that post-polypectomy surveillance intervals should be based on standardised measurements of polyp size, evaluated either during endoscopy or by histological analysis.1 However, at present, no standardised methods exist for measuring polyp size during colonoscopies or through pathology. Consequently, the ESGE states that its recommendation is based on weak and low-quality evidence.1 We conducted within an Institutional Review Board approved (CER21.305; ID: NCT05236790) trial a prospective substudy assessing the feasibility and accuracy of pathology-based polyp sizing. Outcomes of interest were the proportion of all detected polyps for which pathology-based sizing information could be obtained; estimating polyp shrinkage effects because of formalin fixation; proportions of ≥10 mm and ≥5 mm polyps misclassified as <10 and <5 mm because of specimen shrinkage and the relative accuracy of pathology-based polyp size measurement compared with intracolonoscopy polyp size measurements using a …

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  • BNN and DvR are joint senior authors.

  • RD and AK contributed equally.

  • Contributors DvR developed the concept, drafted and revised the manuscript. BNN designed the grossing and measurement protocol in pathology. RD and AK drafted and revised the manuscript. All authors performed data collection, reviewed and approved the final manuscript.

  • Funding This study was funded by Fujifilm, grant number: 21.305.

  • Competing interests DvR is supported by a ‘Fonds de Recherche du Québec Santé’ career development award. He has also received research funding from ERBE Elektromedizin GmbH, Ventage, Pendopharm, Fujifilm and Pentax, and has received consultant or speaker fees from Boston Scientific, ERBE Elektromedizin GmbH and Pendopharm. The remaining authors declare that they have no conflict of interest.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

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