5-Aminosalicylic acid therapy and the risk of colorectal cancer among patients with inflammatory bowel disease

Inflamm Bowel Dis. 2007 Apr;13(4):367-71. doi: 10.1002/ibd.20074.


Background: Patients with inflammatory bowel disease (IBD) affecting the colon are at increased risk of developing colorectal cancer (CRC). Published data are conflicting about whether 5-aminosalicylic acid (5-ASA) has chemopreventive properties against IBD-related carcinogenesis. The objective of this observational study was to determine if an association between 5-ASA therapy and CRC risk exists in IBD patients.

Methods: Adult patients with a new CRC diagnosis (n = 18,440) were identified from 2 large administrative claims databases. For each case, 20 control patients with no record of CRC diagnosis or bowel surgery (n = 368,800) were identified.

Results: An IBD diagnosis was associated with a 6- to 7-fold increased risk of CRC (ulcerative colitis, crude odds ratio [OR] = 6.72, 95% CI, 5.79-7.81; Crohn's disease, crude OR = 6.60, 95% CI, 5.56-7.82). Among patients with IBD (364 CRC cases, 1172 controls), exposure to 5-ASA therapy of any dose or duration during the 12 months before CRC diagnosis was not associated with a reduced risk of CRC (OR = 0.97; 95% CI, 0.77-1.23). However, there was a trend toward a decreased risk of CRC with increasing number of mesalamine prescriptions in the previous year, though statistical significance was not achieved (trend P = 0.08).

Conclusions: Treating IBD patients with 5-ASA medications was not found to have a protective effect against colitis-related CRC when assessed over a short period of exposure.

MeSH terms

  • Aged
  • Anti-Inflammatory Agents, Non-Steroidal / administration & dosage
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use*
  • Case-Control Studies
  • Colorectal Neoplasms / epidemiology
  • Colorectal Neoplasms / etiology
  • Colorectal Neoplasms / prevention & control*
  • Female
  • Humans
  • Inflammatory Bowel Diseases / complications
  • Inflammatory Bowel Diseases / drug therapy*
  • Male
  • Mesalamine / administration & dosage
  • Mesalamine / therapeutic use*
  • Risk
  • Sulfasalazine / administration & dosage
  • Sulfasalazine / therapeutic use*
  • United States / epidemiology


  • Anti-Inflammatory Agents, Non-Steroidal
  • Sulfasalazine
  • Mesalamine