Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK.
Aliment Pharmacol Ther. 2010 Apr;31(7):708-18. doi: 10.1111/j.1365-2036.2010.04238.x. Epub 2010 Jan 18.
Folic acid has been identified as a possible agent for the chemoprevention of colorectal cancer.
To assess the effectiveness of folic acid in reducing the recurrence of adenomas (precursors of colorectal cancer) among populations with a history of adenomas and the incidence of colorectal cancer within average-risk populations.
Systematic review of randomized controlled trials comparing folic acid alone, or with other agents, vs. placebo. Eight databases were searched for relevant trials. Meta-analysis was performed.
The literature search retrieved 3785 citations. Six studies met the inclusion criteria. Meta-analysis of three studies in individuals with a history of adenomas showed no statistically significant difference in the relative risk of adenoma recurrence (RR 0.93, P = 0.27). A sensitivity analysis of the two higher quality trials changed the direction of effect (RR 1.16, P = 0.11). Meta-analysis of three trials in general populations demonstrated no statistically significant effect on the relative risk of colorectal cancer (RR 1.13, P = 0.54). In all three analyses, outcome event rates were higher in individuals receiving folic acid.
There is no evidence that folic acid is effective in the chemoprevention of colorectal adenomas or colorectal cancer for any population.
叶酸已被确定为结直肠肿瘤化学预防的一种可能药物。
评估叶酸在降低有腺瘤病史人群的腺瘤（结直肠肿瘤的前体）复发率和平均风险人群结直肠癌发病率方面的有效性。
对单独使用叶酸或与其他药物联合使用与安慰剂进行比较的随机对照试验进行系统评价。对 8 个数据库进行了相关试验的检索。进行了荟萃分析。
文献检索共检索到 3785 条引用。符合纳入标准的有 6 项研究。对有腺瘤病史的 3 项研究的荟萃分析显示，腺瘤复发的相对风险无统计学显著差异（RR 0.93，P = 0.27）。对两项更高质量试验的敏感性分析改变了效应方向（RR 1.16，P = 0.11）。对一般人群的 3 项试验的荟萃分析显示，对结直肠癌的相对风险无统计学显著影响（RR 1.13，P = 0.54）。在所有 3 项分析中，接受叶酸治疗的个体的结局事件发生率更高。
没有证据表明叶酸对任何人群的结直肠腺瘤或结直肠癌的化学预防有效。
