IBD and the risk of colorectal cancer
The American Gastroenterological Association (AGA) has released a position statement on the risk of colorectal cancer (CRC) in patients with IBD
Inflammatory Bowel Disease (IBD) comprises two distinct disorders—ulcerative colitis and Crohn’s disease—that have different pathological and clinical characteristics.
Ulcerative colitis (UC) is limited to the colon, whereas Crohn’s disease (CD) can affect the entire gastrointestinal tract. However, up to ten percent of patients are described as having “indeterminate” IBD because they display some features of both disorders. There are conflicting estimates regarding the number of Australians who have IBD. According to the Australian Crohn’s and Colitis Association, over 60,000 Australians are affected.The Australian Gastroenterology Institute puts the total number at round 23,000, with 13,000 having ulcerative colitis and 10,000 Crohn’s disease.
5-amino salicylic acid drugs are the standard treatment for acute and maintenance treatment of mild-to-moderate UC induction and maintenance of remission in mild to moderate UC. Their place in the management of intestinal inflammation in CD is not clear.
AGA position statement
According to the AGA, patients with IBD have an increased risk of CRC.6 The exact magnitude of the risk is uncertain, although it is believed to have decreased over recent years because of the chemoprotective effects of aminosalicylates, earlier hemi-colectomy for medically-refractory disease, and colonoscopic surveillance. Factors that place patients with IBD at higher risk of CRC include:
• Extent of disease (most cancers occur in patients with pancolitis)
• Primary sclerosing cholangitis (PSC)
• Positive family history of sporadic CRC in a first-degree relative
• A greater degree of macroscopic and histologic inflammation
• Strictures (especially in UC) and the presence of a shortened colon
• Dysplasia (currently considered the best marker)
Patients with IBD and raised dysplasia should be treated either with colectomy or polpectomy.6 Among patients with high-grade flat dysplasia, colectomy is recommended. It is not clear if it’s beneficial in patients with low-grade flat dysplasia. Surveillance colonoscopy is recommended for patients at increased risk at intervals of 1 to 3 years. Ursodeoxycholic acid has been shown to be highly effective in decreasing the risk of CRC in patients with IBD and PSC. Aminosalicylates are moderately effective at reducing the risk of CRC.