title: Low-grade dysplasia in ulcerative colitis: risk factors for developing high-grade dysplasia or colorectal cancer.
abstract: OBJECTIVE
  The aim of this study was to identify risk factors associated with development of high-grade dysplasia (HGD) or colorectal cancer (CRC) in ulcerative colitis (UC) patients diagnosed with low-grade dysplasia (LGD).
  
  
  METHODS
  Patients with histologically confirmed extensive UC, who were diagnosed with LGD between 1993 and 2012 at St Mark's Hospital, were identified and followed up to 1 July 2013. Demographic, endoscopic, and histological data were collected and correlated with the development of HGD or CRC.
  
  
  RESULTS
  A total of 172 patients were followed for a median of 48 months from the date of initial LGD diagnosis (interquartile range (IQR), 15-87 months). Overall, 33 patients developed HGD or CRC (19.1% of study population; 20 CRCs) during study period. Multivariate Cox proportional hazard analysis revealed that macroscopically non-polypoid (hazard ratio (HR), 8.6; 95% confidence interval (CI), 3.0-24.8; P<0.001) or invisible (HR, 4.1; 95% CI, 1.3-13.4; P=0.02) dysplasia, dysplastic lesions ≥1 cm in size (HR, 3.8; 95% CI, 1.5-13.4; P=0.01), and a previous history of "indefinite for dysplasia" (HR, 2.8; 95% CI, 1.2-6.5; P=0.01) were significant contributory factors for HGD or CRC development. Multifocal dysplasia (HR, 3.9; 95% CI, 1.9-7.8; P<0.001), metachronous dysplasia (HR, 3.5; 95% CI, 1.6-7.5; P=0.001), or a colonic stricture (HR, 7.4; 95% CI, 2.5-22.1; P<0.001) showed only univariate correlation to development of HGD or CRC.
  
  
  CONCLUSIONS
  Lesions that are non-polypoid or endoscopically invisible, large (≥1 cm), or preceded by indefinite dysplasia are independent risk factors for developing HGD or CRC in UC patients diagnosed with LGD.
authors.affiliation: Inflammatory Bowel Disease Unit, St Mark's Hospital, London, UK.|Tumour Biology, Barts Cancer Institute, Charterhouse Square, Queen Mary University of London, London, UK.
authors.forename: Chang-ho Ryan
authors.initials: CH
authors.lastname: Choi
authors.affiliation: Wolfson Unit for Endoscopy, St Mark's Hospital, London, UK.
authors.forename: Ana
authors.initials: A
authors.lastname: Ignjatovic-Wilson
authors.affiliation: Department of Colorectal Surgery, St Mark's Hospital, London, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Askari
authors.affiliation: Department of Colorectal Surgery, St Mark's Hospital, London, UK.
authors.forename: Gui Han
authors.initials: GH
authors.lastname: Lee
authors.affiliation: Department of Colorectal Surgery, St Mark's Hospital, London, UK.
authors.forename: Janindra
authors.initials: J
authors.lastname: Warusavitarne
authors.affiliation: Department of Pathology, St Mark's Hospital, London, UK.
authors.forename: Morgan
authors.initials: M
authors.lastname: Moorghen
authors.affiliation: Wolfson Unit for Endoscopy, St Mark's Hospital, London, UK.
authors.forename: Siwan
authors.initials: S
authors.lastname: Thomas-Gibson
authors.affiliation: Wolfson Unit for Endoscopy, St Mark's Hospital, London, UK.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Saunders
authors.affiliation: University Hospital of North Tees, Teesside, UK.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Rutter
authors.affiliation: Tumour Biology, Barts Cancer Institute, Charterhouse Square, Queen Mary University of London, London, UK.
authors.forename: Trevor A
authors.initials: TA
authors.lastname: Graham
authors.affiliation: Inflammatory Bowel Disease Unit, St Mark's Hospital, London, UK.
authors.forename: Ailsa L
authors.initials: AL
authors.lastname: Hart
mesh_terms: D000368:Aged; D003093:Colitis, Ulcerative / Q000473:pathology*; D003106:Colon / Q000473:pathology*; D003108:Colonic Diseases / Q000473:pathology; D003111:Colonic Polyps / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology*; D003251:Constriction, Pathologic / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors