Inflammatory bowel disease (IBD) is classically subdivided into
ulcerative colitis (UC) and
Crohn's disease (CD). Patients with IBD have increased risk for
colorectal cancer. Because the pathogenesis of
colorectal carcinoma has not been entirely defined yet and there is no ideal treatment for
colon cancer,
cancer prevention has become increasingly important in patients with IBD. The two adopted methods to prevent the development of
colon cancer in clinical practice include the prophylactic
colectomy and colonoscopic surveillance. But patients and physicians seldom accept
colectomy as a routine preventive method and most patients do not undergo appropriate colonoscopic surveillance.
Chemoprevention refers to the use of natural or synthetic chemical agents to reverse, suppress, or to delay the process of
carcinogenesis.
Chemoprevention is a particularly useful method in the management of patients at high risk for the development of specific
cancers based on inborn
genetic susceptibility, the presence of
cancer-associated disease, or other known risk factors. Prevention of
colorectal cancer by administration of chemopreventive agents is one of the most promising options for IBD patients who are at increased risks of the disease. The chemopreventive efficacy of nonsteroidal anti-inflammatory drugs (
NSAIDs) against intestinal
tumors has been well established. But with reports that
NSAIDs aggravated the symptoms of
colitis, their sustained use for the purpose of
cancer chemoprevention has been relatively contraindicated in IBD patients. Another hopeful candidate
chemoprevention drug for IBD patients is
5-aminosalicylic acid (5-ASA), which is well tolerated by most patients and has limited systemic adverse effects, and no gastrointestinal toxicity. 5-ASA lacks the well-known side effects of long-term
NSAIDs use. Retrospective correlative studies have suggested that the long-term use of 5-ASA in IBD patients may significantly reduce the risk of development of
colorectal cancer. According to the literature, this agent might well satisfy clinical expectations with respect to a safe and effective chemopreventive agent.