CHEMOPREVENTION OF COLORECTAL-CANCER IN INFLAMMATORY BOWEL-DISEASE - A POTENTIAL ROLE FOR FOLATE

Patients with ulcerative colitis have an increased risk for developing colon cancer compared to the general population. The, risk is related to the extension of the disease and its duration. This risk is the sa me for Crohn's colitis patients of equal extension and duration. By ch emoprevention we mean the use of specific natural or synthetic chemica l agents to reverse, suppress or prevent progression to invasive cance l: The chemopreventive agents for colon cancer are either of natural o rigin (vitamins, minerals, food constituents) or synthetic chemicals ( difluoromethyl ornithine) and pharmaceutical agents (aspirin, olitpraz ). Apart from folate, no other agent has so far been used in vivo for the prevention of colon cancer in long-standing inflammatory bowel dis ease. The use of folate was, however not primarily intended to prevent cancer but to enhance folate absorption in ulcerative colitis. From r etrospective studies, within the framework of cancer surveillance prog rammes, it became evident that folate supplementation may play a posit ive role as a chemopreventive agent against colorectal cancer in patie nts with long-standing, extensive ulcerative colitis. There is also ev idence suggesting that folate supplementation may contribute to regula tion of rectal cell proliferation in ulcerative colitis patients. Ther e is a real need for multicentre, randomized prospective clinical stud ies in order to evaluate the promising role of folate in preventing co lorectal cancer in patients with long-standing inflammatory bowel dise ase.