Mouzas I A, Papavassiliou E, Koutroubakis I
Gastroenterology Department, University Hospital, Heraklion, Greece.
Ital J Gastroenterol Hepatol. 1998 Aug;30(4):421-5.
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 same for Crohn's colitis patients of equal extension and duration. By chemoprevention we mean the use of specific natural or synthetic chemical agents to reverse, suppress or prevent progression to invasive cancer. The chemopreventive agents for colon cancer are either of natural origin (vitamins, minerals, food constituents) or synthetic chemicals (difluoromethyl ornithine) and pharmaceutical agents (aspirin, oltipraz). Apart from folate, no other agent has so far been used in vivo for the prevention of colon cancer in long-standing inflammatory bowel disease. The use of folate was, however, not primarily intended to prevent cancer but to enhance folate absorption in ulcerative colitis. From retrospective studies, within the framework of cancer surveillance programmes, it became evident that folate supplementation may play a positive role as a chemopreventive agent against colorectal cancer in patients with long-standing, extensive ulcerative colitis. There is also evidence suggesting that folate supplementation may contribute to regulation of rectal cell proliferation in ulcerative colitis patients. There is a real need for multicentre, randomized, prospective clinical studies in order to evaluate the promising role of folate in preventing colorectal cancer in patients with long-standing inflammatory bowel disease.
与普通人群相比，溃疡性结肠炎患者患结肠癌的风险增加。这种风险与疾病的范围及其持续时间有关。对于病变范围和持续时间相同的克罗恩结肠炎患者，这种风险是一样的。化学预防是指使用特定的天然或合成化学制剂来逆转、抑制或预防进展为浸润性癌。用于结肠癌的化学预防剂要么是天然来源的（维生素、矿物质、食物成分），要么是合成化学物质（二氟甲基鸟氨酸）以及药物制剂（阿司匹林、奥替普拉）。除了叶酸，到目前为止还没有其他制剂在体内用于预防长期炎症性肠病患者的结肠癌。然而，使用叶酸主要目的不是预防癌症，而是提高溃疡性结肠炎患者的叶酸吸收。从癌症监测项目框架内的回顾性研究中可以明显看出，补充叶酸可能作为化学预防剂对长期广泛性溃疡性结肠炎患者预防结直肠癌起到积极作用。也有证据表明，补充叶酸可能有助于调节溃疡性结肠炎患者直肠细胞的增殖。确实需要进行多中心、随机、前瞻性临床研究，以评估叶酸在预防长期炎症性肠病患者结直肠癌方面的潜在作用。
