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

Abstract

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% 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 (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.

MicroRNA‑449a is a potential predictor of colitis‑associated colorectal cancer progression

“…Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is characterized by the idiopathic, chronic and recurrent inflammatory conditions of the human bowel and is an important risk factor for developing CRC, thus called colitis-associated colorectal cancer (CAC) (2,3). UC patients with refractory and long-standing disease duration are reported to have a significantly increased cancer risk which increases with the earlier age of disease onset, the duration of the disease and the extent of colonic involvement (4,5). Eaden et al (6) estimated the cumulative cancer incidence for developing CAC as 2% at 10 years, 8% at 20 years and 18% at 30 years in patients affected by chronic colitis using a widely cited meta-analysis of 116 studies with age stratified data.…”

Clinical characteristics of ulcerative colitis‐related colorectal cancer in Chinese patients

“…Our findings are consistent with these risk factors. Interestingly, there were no PSC cases in our cohort, which may be explained by the lower prevalence of PSC in Chinese patients with UC than in those in Western countries …”

Consecutive negative findings on colonoscopy during surveillance predict a low risk of advanced neoplasia in patients with inflammatory bowel disease with long-standing colitis: results of a 15-year multicentre, multinational cohort study

“…We further made our definition of a ‘negative’ colonoscopy strict in order to truly define a lower risk IBD population, but also to maximise use of objective measures to enhance clinical reproducibility and facility in a practice-based setting. Patient characteristics including PSC,16 17 family history of CRC18 and personal history of neoplasia,19 as well as endoscopic features including strictures,20 inflammation,21 22 and postinflammatory polyps20 23 24 have all been shown to increase the risk of subsequent neoplastic transformation in IBD colitis; thus, complete absence of these features was necessary to meet criteria for a negative investigation. Based on these criteria, less than 30% of patients in our database had high-risk demographics that necessitated yearly surveillance colonoscopies.…”

“…For patients with IBD, the risk of CRC is broadly estimated to be increased by a factor of 2, although numbers vary according to the population studied 2 27. Nevertheless, caution should be exercised when comparing neoplasia outcomes between patients with IBD and without IBD, particularly since the trajectory of dysplasia progression is, generally speaking, more rapid in the former and implicates nuances in the dysplasia–carcinoma sequence 19. Indeed, CRC screening intervals for patients without IBD may safely extend up to 10 years, far more prolonged than the currently recommended screening intervals in patients with long-standing IBD colitis 8 28 29…”