title: Chemopreventive effects of 5-aminosalicylic acid on inflammatory bowel disease-associated colorectal cancer and dysplasia: a systematic review with meta-analysis.
abstract: OBJECTIVE
  The chemopreventive effect of 5-aminosalicylic acid (5-ASA) in patients with inflammatory bowel disease (IBD) has been widely studied; however, the results remain conflicting. The aim of this study was to systematically review the literature and update evidence concerning effects of 5-ASA on the risk of colorectal cancer (CRC) and dysplasia (Dys) in patients with ulcerative colitis (UC) or Crohn's disease (CD).
  
  
  RESULTS
  5-ASA showed a chemopreventive effect against CRC/Dys in IBD patients (OR = 0.58, 95% CI: 0.45-0.75). However, this effect was significant only in clinical-based studies (OR = 0.51; 95% CI: 0.39-0.65), but not in population-based studies (OR = 0.71; 95% CI: 0.46-1.09). Moreover, this effect was noticeable in patients with UC (OR = 0.46, 95% CI: 0.34-0.61), but not in CD (OR = 0.66, 95% CI: 0.42-1.03), and on the outcome of CRC (OR = 0.54, 95% CI: 0.39-0.74), but not Dys (OR = 0.47; 95% CI: 0.20-1.10). In IBD patients, mesalazine dosage ≥ 1.2 g/day showed greater protective effects against CRC/Dys than dosages < 1.2 g/day. However, Sulphasalazine therapy did not show any noticeable protective function regardless of the dosage administered.
  
  
  METHODS
  We performed a systematic review with a meta-analysis of 26 observational studies involving 15,460 subjects to evaluate the risks of developing CRC and Dys in IBD patients receiving 5-ASA treatment. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each evaluation index.
  
  
  CONCLUSIONS
  5-ASA has a chemopreventive effect on CRC (but not Dys) in IBD patients. Moreover, UC patients can benefit more from 5-ASA than CD patients. Mesalazine maintenance dosage ≥ 1.2 g/day is an effective treatment for reducing CRC risk in IBD patients.
authors.affiliation: Department of Gastroenterology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Xinyun
authors.initials: X
authors.lastname: Qiu
authors.affiliation: Department of Gastroenterology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Ma
authors.affiliation: Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D018890:Chemoprevention; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000209:etiology* / Q000517:prevention & control*; D006801:Humans; D006965:Hyperplasia; D015212:Inflammatory Bowel Diseases / Q000150:complications* / Q000188:drug therapy* / Q000473:pathology; D019804:Mesalamine / Q000627:therapeutic use*; D016017:Odds Ratio; D011159:Population Surveillance; D017594:Publication Bias; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D019804:Mesalamine
keywords: 5-Aminosalicylic acid; chemopreventive effect; colorectal cancer; dysplasia; inflammatory bowel disease