title: Incidence, Risk Factors, and Outcomes of Colorectal Cancer in Patients With Ulcerative Colitis With Low-Grade Dysplasia: A Systematic Review and Meta-analysis.
abstract: OBJECTIVE
  Little is known about outcomes of patients with ulcerative colitis with low-grade dysplasia (UC-LGD). We estimated the incidence of and risk factors for progression to colorectal cancer (CRC) in cohorts of patients with UC-LGD who underwent surveillance (surveillance cohort), and the prevalence of dysplasia-related findings among patients who underwent colectomy for UC-LGD (surgical cohort).
  
  
  METHODS
  We performed a systematic literature review through June 1, 2016, to identify cohort studies of adults with UC-LGD. We estimated pooled incidence rates of CRC and risk factors associated with dysplasia progression in surveillance cohorts, and prevalence of synchronous advanced neoplasia (CRC and/or high-grade dysplasia) in surgical cohorts.
  
  
  RESULTS
  In 14 surveillance cohort studies of 671 patients with UC-LGD (52 developed CRC), the pooled annual incidence of CRC was 0.8% (95% confidence interval [CI], 0.4-1.3); the pooled annual incidence of advanced neoplasia was 1.8% (95% CI, 0.9-2.7). Risk of CRC was higher when LGD was diagnosed by expert gastrointestinal pathologist (1.5%) than by community pathologists (0.2%). Factors significantly associated with dysplasia progression were concomitant primary sclerosing cholangitis (odds ratio [OR], 3.4; 95% CI, 1.5-7.8), invisible dysplasia (vs visible dysplasia; OR, 1.9; 95% CI, 1.0-3.4), distal location (vs proximal location; OR, 2.0; 95% CI, 1.1-3.7), and multifocal dysplasia (vs unifocal dysplasia; OR, 3.5; 95% CI, 1.5-8.5). In 12 surgical cohort studies of 450 patients who underwent colectomy for UC-LGD, 34 patients had synchronous CRC (pooled prevalence, 17%; 95% CI, 8-33).
  
  
  CONCLUSIONS
  In a systematic review of the literature, we found that among patients with UC-LGD under surveillance, the annual incidence of progression to CRC was 0.8%; differences in rates of LGD diagnosis varied with pathologists' level of expertise. Concomitant primary sclerosing cholangitis, invisible dysplasia, distal location, and multifocal LGD are high-risk features associated with dysplasia progression.
authors.affiliation: Division of Gastroenterology, University of California San Diego, La Jolla, California; Gastroenterology Unit, Amiens University and Hospital, Université de Picardie Jules Verne, Amiens, France.
authors.forename: Mathurin
authors.initials: M
authors.lastname: Fumery
authors.affiliation: Division of Gastroenterology, University of California San Diego, La Jolla, California.
authors.forename: Parambir S
authors.initials: PS
authors.lastname: Dulai
authors.affiliation: Division of Gastroenterology, University of California San Diego, La Jolla, California; Division of Gastroenterology, San Diego Veterans Affairs Healthcare System, La Jolla, California.
authors.forename: Samir
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Department of Library Services, Mayo Clinic, Rochester, Minnesota.
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Prokop
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, University of California San Diego, La Jolla, California.
authors.forename: Sonia
authors.initials: S
authors.lastname: Ramamoorthy
authors.affiliation: Division of Gastroenterology, University of California San Diego, La Jolla, California.
authors.forename: William J
authors.initials: WJ
authors.lastname: Sandborn
authors.affiliation: Division of Gastroenterology, University of California San Diego, La Jolla, California; Division of Biomedical Informatics, University of California San Diego, La Jolla, California. Electronic address: sis040@ucsd.edu.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Singh
mesh_terms: D003082:Colectomy / Q000706:statistics & numerical data; D003093:Colitis, Ulcerative / Q000150:complications*; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000601:surgery; D006801:Humans; D015994:Incidence; D015995:Prevalence; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Cancer; Colectomy; Inflammatory Bowel Diseases; PSC; Proliferation