title: Prospective study of the progression of low-grade dysplasia in ulcerative colitis using current cancer surveillance guidelines.
abstract: BACKGROUND
  The goal of this study was to assess the natural history of low-grade dysplasia (LGD) and its risk of progression in ulcerative colitis (UC) patients by prospective endoscopic surveillance.
  
  
  METHODS
  Forty-two UC patients with LGD were followed prospectively using a uniform approach to surveillance colonoscopy with an average of 43 biopsies per exam. The interval between colonoscopies ranged from 3-12 months. Progression was defined as development of high-grade dysplasia (HGD) or cancer at subsequent colonoscopy or at colectomy. Univariate and multivariate analysis were performed to identify risk factors associated with progression.
  
  
  RESULTS
  Patients were followed for an average of 3.9 years (range 1-13). Over that period 19% (8/42) of patients progressed to advanced neoplasia (two cancer, six HGD) while 17% (7/42) had persistent LGD and 64% (27/42) had indefinite dysplasia or no dysplasia at the end of follow-up. Multivariate analysis demonstrated that the number of biopsies with LGD at baseline was associated with an increased risk of progression to advanced neoplasia (relative risk [RR] 5.8, 95% confidence interval [CI]: (1.29-26.04). Among the 15 patients who underwent colectomy, four were found to have higher-grade neoplasia on their colectomy specimen than their preoperative colonoscopy, and these patients were more likely to be nonadherent with recommendations for colectomy.
  
  
  CONCLUSIONS
  The majority (81%) of UC patients with LGD did not progress to higher grades of dysplasia during a 4-year follow-up. Patients with three or more biopsies demonstrating LGD at a single colonoscopy were at increased risk for progression to advanced neoplasia.
authors.affiliation: Department of Medicine, University of Washington Medical Center, Seattle, Washington 98195, USA.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Zisman
authors.forename: Mary P
authors.initials: MP
authors.lastname: Bronner
authors.forename: Stephen
authors.initials: S
authors.lastname: Rulyak
authors.forename: Kris V
authors.initials: KV
authors.lastname: Kowdley
authors.forename: Michael
authors.initials: M
authors.lastname: Saunders
authors.forename: Scott D
authors.initials: SD
authors.lastname: Lee
authors.forename: Cynthia
authors.initials: C
authors.lastname: Ko
authors.forename: Michael B
authors.initials: MB
authors.lastname: Kimmey
authors.forename: Allyn
authors.initials: A
authors.lastname: Stevens
authors.forename: Josephine
authors.initials: J
authors.lastname: Maurer
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Brentnall
mesh_terms: D000328:Adult; D000368:Aged; D003093:Colitis, Ulcerative / Q000150:complications* / Q000473:pathology; D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000473:pathology; D003113:Colonoscopy; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D011230:Precancerous Conditions / Q000209:etiology* / Q000473:pathology; D011446:Prospective Studies; D012307:Risk Factors