title: Reliability of the reported size of removed colorectal polyps.
abstract: BACKGROUND
  The size of colorectal polyps is important in the clinical management of these lesions.
  
  
  OBJECTIVE
  To audit the accuracy in calculating the size of "polyps" by various specialists.
  
  
  METHODS
  Eighteen pathologists and four surgeons measured, with a conventional millimetre ruler, the largest diameter of 12 polyp phantoms. The results of two independent measurements (two weeks apart) were compared with the gold standard-size assessed at The Royal Institute of Technology, Sweden.
  
  
  RESULTS
  Thirty-one percent (83/264-trial 1) and 33% (88/264-trial 2) of the measurements underestimated or overestimated the gold standard size by >1 mm. Of the 22 experienced participants, 95% (21/22-trial 1) and 91% (20/22-trial 2) misjudged by >1 mm the size of one or more polyps. Values given by 13 participants (4.9%) in trial 1 and by 15 participants (5.7%) in trial 2, differed by > or = +/-4 mm from the gold standard size. In addition, a big difference between the highest and the lowest values was recorded in some polyps (up to 11.4 mm). Those disparate values were regarded as a human error in reading the scale on the ruler.
  
  
  CONCLUSIONS
  Using a conventional ruler (the tool of pathologists worldwide) unacceptably high intra-observer and inter-observer variations in assessing the size of polyp-phantoms was found. The volume and the shape of devices, as well as human error in reading the scale of the ruler were confounding factors in size assessment. In praxis, the size is crucial in the management of colorectal polyps. Considering the clinical implications of the results obtained, the possibility of developing a method that will allow assessment of the true size of removed clinical polyps is being explored.
authors.affiliation: Department of Pathology Karolinska University Hospital, Stockholm, Solna, Sweden. Carlos.Rubio@onkpat.ki.se
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Rubio
authors.forename: Lars
authors.initials: L
authors.lastname: Grimelius
authors.forename: Johan
authors.initials: J
authors.lastname: Lindholm
authors.forename: Hans
authors.initials: H
authors.lastname: Hamberg
authors.forename: Anja
authors.initials: A
authors.lastname: Porwit
authors.forename: Göran
authors.initials: G
authors.lastname: Elmberger
authors.forename: Anders
authors.initials: A
authors.lastname: Höög
authors.forename: Lena
authors.initials: L
authors.lastname: Kanter
authors.forename: Elina
authors.initials: E
authors.lastname: Eriksson
authors.forename: Sten
authors.initials: S
authors.lastname: Stemme
authors.forename: Abiel
authors.initials: A
authors.lastname: Orrego
authors.forename: Leonie
authors.initials: L
authors.lastname: Saft
authors.forename: Fredrik
authors.initials: F
authors.lastname: Petersson
authors.forename: Manuel
authors.initials: M
authors.lastname: De La Torre
authors.forename: Christina
authors.initials: C
authors.lastname: Ekström
authors.forename: Kristina
authors.initials: K
authors.lastname: Astrom
authors.forename: Asa
authors.initials: A
authors.lastname: Rundgren
authors.forename: Miroslav
authors.initials: M
authors.lastname: Djokic
authors.forename: E
authors.initials: E
authors.lastname: Chandanos
authors.forename: Claes
authors.initials: C
authors.lastname: Lenander
authors.forename: Mikael
authors.initials: M
authors.lastname: Machado
authors.forename: Per
authors.initials: P
authors.lastname: Nilsson
authors.forename: Lars
authors.initials: L
authors.lastname: Mattsson
mesh_terms: D003108:Colonic Diseases / Q000473:pathology*; D006801:Humans; D007417:Intestinal Polyps / Q000473:pathology*; D015588:Observer Variation; D010336:Pathology / Q000379:methods / Q000592:standards; D012002:Rectal Diseases / Q000473:pathology*; D015203:Reproducibility of Results