经济学人下载:阿司匹林让人吃惊的另一面

Science and Technology Prevention of cancer Wonder drug
科技 预防癌症 特效药

Aspirin continues to amaze
阿司匹林让人吃惊的另一面

FOR thousands of years aspirin has been humanity's wonder drug.
几千年来，阿司匹林就一直是人类的特效药。

Extracts from the willow tree have been used for pain relief in folk medicine since the time of the ancient Greeks.
从古希腊开始，在民间医药中，人们就用柳树的萃取物缓解疼痛。

By 1897 a synthetic derivative (acetyl salicylic acid) of the plant's active ingredient (salicin) was created. This allowed aspirin to become the most widely used medicine in the world.
1897年，这种植物中的有效成分的人工合成衍生物诞生了，于是阿司匹林变成了世界上应用最广泛的药品。

In recent years its benefits as a blood-thinning drug have led to it being prescribed in low doses of around 50mg to reduce deaths from stroke and heart attack.
最近几年，由于阿司匹林的防血凝功能，在用其治疗中风和心脏病的时候，剂量很小，维持在50mg的水平左右。

There were also hints that aspirin may help prevent some cancers.
也有迹象表明阿司匹林可以帮助预防一些癌症。

But these were mostly based on observational studies, which can be misleading.
不过这些结论大多都是在观察研究的基础上的，因而有可能产生误导。

The gold standard of scientific evidence is the randomised controlled trial, preferably one with a lot of people and held over a long time.
国际上科学证据的标准是由随机对照实验得出的结果，尤其是那些有很多人参与又经过很长时间的实验。

The results of just such a trial, published in the Lancet, suggest that aspirin is indeed an astonishing drug.
而就是这样一份发表在《柳叶刀》上的论文表示阿司匹林的确是一种让人吃惊的药物。

Peter Rothwell at the John Radcliffe Hospital in Oxford and his colleagues looked at deaths due to cancers during and after randomised trials of daily aspirin.
来自牛津的约翰·拉德克里夫医院的彼得·罗思韦尔（Peter Rothwell）和他的同事们研究了在每日服用阿司匹林的随机对照实验期间或者之后因癌症而死亡的病例。

The trials had actually been started to look at how useful aspirin was for preventing heart attacks and strokes. Nevertheless, the data from the 25,570 patients enrolled in eight trials was also revealing about cancer.
这一实验本是为了研究阿司匹林在防止心脏病和中风方面的疗效的，然而八项试验25570名患者的数据也揭示了阿司匹林对于癌症的疗效。

In trials lasting between four and eight years, the patients who had been given aspirin were 21% less likely to die from cancer than those who had been given a placebo.
在那些历时4到8年之间的实验中，服用阿司匹林的患者因癌症而死亡的概率比那些服用安慰剂的患者小了21%。

These results were based on 674 cancer deaths, so are unlikely to represent the kind of statistical oddity that can beset studies on cancer risks that sometimes create headlines.
这些结果是在674例癌症死亡病例的基础上得出的，所以不大可能是所谓的统计学上的例外。对癌症风险的研究会因这种例外而受挫，有时甚至会闹成大新闻。

The benefits of aspirin were also apparent many years after the trials had ended.
试验结束后的很多年后，阿司匹林的效果也仍旧明显。

After five years, death rates for all cancers fell by 35% and for gastrointestinal cancers by 54%.
五年后，所有癌症的死亡率下降了35%，而胃肠道癌症的死亡率则下降了54%。

A long-term follow-up of patients showed that the 20-year risk of cancer death remained 20% lower in those who had taken aspirin.
一项长期的病情跟踪报告显示，那些服用阿司匹林的患者的20年内的癌症死亡风险比那些不服用的低了20%。

The study revealed that the effect takes time to accrue, so aspirin must be taken over a long period.
这项研究揭示了阿司匹林的效果是随着时间而递增的，所以必须长期服用才行。

The latent period for improving oesophageal, pancreatic, brain and lung cancer was about five years of aspirin taking on a daily basis.For stomach and colorectal cancer the effects took ten years and for prostate cancer about 15 years.
每日服用阿司匹林对改善食管癌，胰腺癌，脑癌和肺癌的潜伏期为5年，对胃癌和结直肠癌则要花10年才能起作用，而前列腺癌则要15年。

The means by which aspirin prevents cancer is not well understood.
这意味着目前还不清楚阿司匹林到底是怎么预防癌症的。

It is believed that it inhibits an enzyme that promotes cell proliferation in tumours.
研究人员认为阿司匹林阻碍了一种在肿瘤内部促进细胞增殖的酶的活动。

The researchers also found that small daily doses of aspirin were enough, and that taking more than 75mg conferred no additional benefits.
研究者还发现，每天服用小剂量的阿司匹林就已足够，剂量超过75mg后不会再增加效果。

Those starting on aspirin in their late 40s or 50s benefit most.
那些从四五十岁末就开始服用阿司匹林的人得到的效果最好。

Current guidelines on using aspirin for reducing the chances of a stroke or heart attack rightly warn of the small risk of ulcers and of dangerous bleeding in the stomach.
目前在用阿司匹林治疗中风或者心脏病时，用药说明上会明确提醒有可能出现溃疡和危险性胃出血。

These guidelines will probably have to be revised given the new findings.
而鉴于这些新发现，这些说明很可能将要被修改了。

However, it remains unlikely that popping aspirin will be recommended for everyone like a vitamin supplement.
不过阿司匹林泡腾片不大可能像维生素补充剂一样被推广至每一个人。

Aspirin is a highly cost-effective treatment: taking it for five to ten years easily beats initiatives to screen for breast and prostate cancers.
服用阿司匹林是一种非常划算的治疗：只要吃五到十年，就能打败那些让你做乳腺癌或者前列腺癌扫描的建议。

To put it another way, ask yourself what a pharmaceuticals firm might charge for a drug that would reduce the chance of death by cancer by 20%—and then note that 100 days' supply of low-dose aspirin can cost less than a dollar.
换种说法，问问你自己，什么样的医药公司在看到100天的小剂量阿司匹林供应量还值不到一美元时，会对这种能够减少20%癌症死亡几率的药品开价呢？

By anyone's measure, that is a bargain.
不管按照哪一方的标准，这都是一笔非常划算的交易。