Incidence, Risk Factors, and Outcomes of Colorectal Cancer in Patients With Ulcerative Colitis With Low-Grade Dysplasia: A Systematic Review and Meta-analysis

Clin Gastroenterol Hepatol. 2017 May;15(5):665-674.e5. doi: 10.1016/j.cgh.2016.11.025. Epub 2016 Dec 1.


Background & aims: 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).

Conclusion: 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.

Keywords: Cancer; Colectomy; Inflammatory Bowel Diseases; PSC; Proliferation.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Colectomy / statistics & numerical data
  • Colitis, Ulcerative / complications*
  • Colorectal Neoplasms / epidemiology*
  • Colorectal Neoplasms / surgery
  • Humans
  • Incidence
  • Prevalence
  • Risk Factors
  • Treatment Outcome