阿司匹林抗癌的研究结果近来时有报道。英国一项最新研究显示，长期服用阿司匹林可显著降低患肠癌的风险。这是第一个基于长期随机对比试验的结果，为阿司匹林的抗癌效果提供了有力证据。
英国纽卡斯尔大学等机构的研究人员10月28日在英国医学刊物《柳叶刀》网站上报告了这项成果。研究开始于1999年，共有800多名参与者被随机分为两组，其中一组每天服用600毫克阿司匹林，服药时间至少持续两年，另一组则作为对照。
这些参与者多是一种名为林奇综合征的疾病患者，这是一种遗传疾病，患者由于基因问题而有较高的肠癌风险。但到2010年时进行的跟踪调查显示，服用阿司匹林一组人患肠癌的比例大大低于对照组，只有后者的约一半，那些长期服用阿司匹林的人患癌风险更是可以降低60%以上。
领导研究的约翰·伯恩教授说，这项研究揭示的是阿司匹林在防癌方面的长期效果，这种效果在短期内不一定显现，需要多年之后才能看到服用阿司匹林的好处。
他也提醒说，阿司匹林有一些副作用，比如容易导致胃溃疡等，人们需要根据自身的实际情况来决定是否长期服用阿司匹林。但总的来说，有林奇综合征等遗传病而患癌风险较高的人群服用阿司匹林应是利大于弊。（生物谷 Bioon.com)
doi:10.1016/S0140-6736(11)61049-0
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Long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer: an analysis from the CAPP2 randomised controlled trial
Prof Sir John Burn MD a , Prof Anne-Marie Gerdes MD a b, Prof Finlay Macrae MD c, Prof Jukka-Pekka Mecklin MD d, Gabriela Moeslein MD e, Sylviane Olschwang MD f, Prof Diane Eccles MD g, Prof D Gareth Evans MD h, Prof Eamonn R Maher MD i, Lucio Bertario MD j, Marie-Luise Bisgaard MD k, Prof Malcolm G Dunlop MD l, Judy WC Ho MD m, Prof Shirley V Hodgson MD n, Prof Annika Lindblom MD o, Prof Jan Lubinski MD p, Prof Patrick J Morrison MD q, Victoria Murday MD r, Prof Raj Ramesar PhD s, Lucy Side MD
Background
Observational studies report reduced colorectal cancer in regular aspirin consumers. Randomised controlled trials have shown reduced risk of adenomas but none have employed prevention of colorectal cancer as a primary endpoint. The CAPP2 trial aimed to investigate the antineoplastic effects of aspirin and a resistant starch in carriers of Lynch syndrome, the major form of hereditary colorectal cancer; we now report long-term follow-up of participants randomly assigned to aspirin or placebo.
Methods
In the CAPP2 randomised trial, carriers of Lynch syndrome were randomly assigned in a two-by-two factorial design to 600 mg aspirin or aspirin placebo or 30 g resistant starch or starch placebo, for up to 4 years. Randomisation was in blocks of 16 with provision for optional single-agent randomisation and extended postintervention double-blind follow-up; participants and investigators were masked to treatment allocation. The primary endpoint was development of colorectal cancer. Analysis was by intention to treat and per protocol. This trial is registered, ISRCTN59521990.
Results
861 participants were randomly assigned to aspirin or aspirin placebo. At a mean follow-up of 55·7 months, 48 participants had developed 53 primary colorectal cancers (18 of 427 randomly assigned to aspirin, 30 of 434 to aspirin placebo). Intention-to-treat analysis of time to first colorectal cancer showed a hazard ratio (HR) of 0·63 (95% CI 0·35—1·13, p=0·12). Poisson regression taking account of multiple primary events gave an incidence rate ratio (IRR) of 0·56 (95% CI 0·32—0·99, p=0·05). For participants completing 2 years of intervention (258 aspirin, 250 aspirin placebo), per-protocol analysis yielded an HR of 0·41 (0·19—0·86, p=0·02) and an IRR of 0·37 (0·18—0·78, p=0·008). No data for adverse events were available postintervention; during the intervention, adverse events did not differ between aspirin and placebo groups.
Interpretation
600 mg aspirin per day for a mean of 25 months substantially reduced cancer incidence after 55·7 months in carriers of hereditary colorectal cancer. Further studies are needed to establish the optimum dose and duration of aspirin treatment.
Funding
European union; Cancer Research UK; Bayer Corporation; National Starch and Chemical Co; UK Medical Research Council; Newcastle Hospitals trustees; Cancer Council of Victoria Australia; THRIPP South Africa; The Finnish Cancer Foundation; SIAK Switzerland; Bayer Pharma.
