Dove-Edwin I, Thomas H J
ICRF Family Cancer Clinic, St Mark's Hospital, Harrow, Middlesex, UK.
Aliment Pharmacol Ther. 2001 Mar;15(3):323-36. doi: 10.1046/j.1365-2036.2001.00934.x.
Colorectal cancer is a leading cause of cancer mortality in the industrialized world. Survival remains poor because most cases are diagnosed at an advanced stage. It is a preventable disease as colorectal cancers usually develop slowly from an identifiable precursor lesion, the adenoma. The existing strategies for colorectal cancer prevention include dietary prevention, chemoprevention and endoscopic intervention. The exact relationship between diet, particularly fibre, and colorectal cancer remains unclear, with the most recent studies suggesting that dietary fibre may not decrease colorectal cancer risk as previously thought. Non-steroidal anti-inflammatory drugs have been shown to have a protective effect against colorectal cancer, but the adverse effect profile of the non COX-2 selective drugs, particularly the risk of gastrointestinal haemorrhage, precludes their widespread use. There is increasing evidence that colorectal cancer incidence and mortality can be decreased from endoscopic polypectomy and early detection of cancer. Faecal occult blood testing in the general population ('average-risk') has been shown in randomized trials to decrease mortality from colorectal cancer by 15--33%. Long-term results of randomized trials of the effectiveness of flexible sigmoidoscopy and colonoscopy screening in the general population are awaited. Targeting high risk individuals may also be an effective and efficient way to decrease the colorectal cancer burden. As many as 15--30% of colorectal cases may be due to hereditary factors. Individuals with one or two direct relatives affected are at moderate risk for colorectal cancer (empirical lifetime mortality from colorectal cancer approximately 10%) and approximately 2--3% of cases arise in individuals harbouring highly penetrant autosomal dominant mutations, which puts them at high-risk for colorectal cancer. Surveillance colonoscopy is offered to individuals at moderate and high risk for colorectal cancer.
在工业化国家，结直肠癌是导致癌症死亡的主要原因之一。由于大多数病例在晚期才被诊断出来，其生存率仍然很低。结直肠癌是一种可预防的疾病，因为结直肠癌通常从一种可识别的前驱病变——腺瘤缓慢发展而来。现有的结直肠癌预防策略包括饮食预防、化学预防和内镜干预。饮食，特别是膳食纤维与结直肠癌之间的确切关系仍不清楚，最近的研究表明，膳食纤维可能不会像以前认为的那样降低患结直肠癌的风险。非甾体抗炎药已被证明对结直肠癌有保护作用，但非COX-2选择性药物的不良反应，特别是胃肠道出血的风险，使其无法广泛使用。越来越多的证据表明，内镜下息肉切除术和癌症的早期检测可以降低结直肠癌的发病率和死亡率。在普通人群（“平均风险”）中进行粪便潜血试验的随机试验表明，该试验可使结直肠癌死亡率降低15%至33%。普通人群中柔性乙状结肠镜检查和结肠镜检查筛查有效性的随机试验的长期结果仍有待观察。针对高危个体也可能是减轻结直肠癌负担的一种有效方法。多达15%至30%的结直肠癌病例可能归因于遗传因素。有一两个直系亲属患结直肠癌的个体患结直肠癌的风险为中度（结直肠癌的经验性终身死亡率约为10%），约2%至3%的病例发生在携带高外显率常染色体显性突变的个体中，这使他们患结直肠癌的风险很高。对于结直肠癌中度和高危个体，会提供监测结肠镜检查。
