2017.9.16經濟學人官譯：圍攻癌症

Health care

Closing in on cancer

Science will win the technical battle against cancer. But that is only half the fight

醫療保健

圍攻癌症

科學將打贏抗擊癌症的技術戰。但那只是戰場的一半

THE numbers are stark. Cancer claimed the lives of 8.8m people in 2015; only heart disease caused more deaths. Around 40% of Americans will be told they have cancer during their lifetimes. It is now a bigger killer of Africans than malaria. But the statistics do not begin to capture the fear inspired by cancer』s silent and implacable cellular mutiny. Only Alzheimer』s exerts a similar grip on the imagination.數字是慘烈的。2015年癌症奪走了880萬人的生命，只有因心臟病死亡的人數比這更高。約40%的美國人一生中會被告知罹患癌症。對於非洲人來說，如今癌症比瘧疾的殺傷力更大。但是統計數據遠遠不能體現癌症帶來的恐懼——細胞變異悄無聲息地發生著，卻絕不留情。只有阿爾茨海默症能如此抓住人的想像力。

Confronted with this sort of enemy, people understandably focus on the potential for scientific breakthroughs that will deliver a cure. Their hope is not misplaced. Cancer has become more and more survivable over recent decades owing to a host of advances, from genetic sequencing to targeted therapies. The five-year survival rate for leukemia in America has almost doubled, from 34% in the mid-1970s to 63% in 2006-12. America is home to about 15.5m cancer survivors, a number that will grow to 20m in the next ten years. Developing countries have made big gains, too: in parts of Central and South America, survival rates for prostate and breast cancer have jumped by as much as a fifth in only a decade.面對這樣的敵人，可以理解人們為何如此關注科學取得突破、發現抗癌良方的可能性。他們的希望並沒落空。從基因測序到靶向治療，由於這些手段取得的進展，近幾十年來癌症患者的存活率越來越高。在美國，白血病的五年存活率從上世紀70年代中期的34%提高到2006年至2012年間的63%，幾乎翻了一番。美國有大約1550萬癌症倖存者，今後十年這個數字將增至2000萬。發展中國家也取得了相當大的進步：在中南美洲部分地區，短短十年內，前列腺癌和乳腺癌的存活率上升了五分之一。

From a purely technical perspective, it is reasonable to expect that science will one day turn most cancers into either chronic diseases or curable ones. But cancer is not fought only in the lab. It is also fought in doctors』 surgeries, in schools, in public-health systems and in government departments. The dispatches from these battlefields are much less encouraging.從純技術的角度看，我們有理由相信，有朝一日科學會將大多數癌症轉化為慢性病或可治癒的病症。但是抗擊癌症的戰鬥不僅僅是在實驗室里展開，手術室、學校、公共衛生系統還有政府部門也是戰場。從這些戰場傳來的訊息就遠沒那麼令人歡欣鼓舞了。

Cell-side research

First, the good news. Caught early, many cancers are now highly treatable. Three out of four British men who received a prostate-cancer diagnosis in the early 1970s did not live for another ten years; today four out of five do. Other cancers, such as those of the lung, pancreas and brain, are harder to find and treat. But as our Technology Quarterly shows, progress is being made. Techniques to enable early diagnosis include a device designed to detect cancer on the breath; blood tests can track fragments of DNA shed from tumours. Genome sequencing makes it ever easier to identify new drug targets.

實驗室研究

先來看看好消息。如果發現得早，現在很多癌症都可以得到很好的治療。上世紀70年代早期，被診斷為前列腺癌的英國患者中有四分之三活不過十年，而現在五分之四的患者可以再活十年。有些癌症較難發現也較難治療，比如肺癌、胰腺癌和腦癌。但正如我們的《科技季刊》所報道的那樣，在這方面還是取得了一些進展。有一項早期診斷技術是一種可通過呼吸來探測癌症的設備；血液測試可以追蹤從腫瘤上脫落的DNA碎片。基因組測序也讓確定新葯標靶變得愈加容易。

The established trio of 20th-century cancer treatments—surgery, radiation and chemotherapy—are all still improving. Radiotherapists can create webs of gamma rays, whose intersections deliver doses high enough to kill tumours but which do less damage to healthy tissue as they enter and leave the body. Some new drugs throttle the growth of blood vessels bringing nutrients to tumours; others attack cancer cells』 own DNA-repair kits. Cancer may be relentless; so too is science. 二十世紀的標準抗癌「三重奏」——手術、放療和化療——都還在不斷改進。放射科醫師可以使用伽馬射線立體定向治療，其射線相交的輻射劑量足以殺死腫瘤，但當射線穿越人體時對健康組織的損害較小。一些新葯能抑製為腫瘤輸送營養物質的血管生長，還有一些新葯會攻擊癌細胞的DNA自我修復機制。癌症或許殘酷無情，但科學也一樣。

The greatest excitement is reserved for immunotherapy, a new approach that has emerged in the past few years. The human immune system is equipped with a set of brakes that cancer cells are able to activate; the first immunotherapy treatment in effect disables the brakes, enabling white blood cells to attack the tumours. It is early days, but in a small subset of patients this mechanism has produced long-term remissions that are tantamount to cures. Well over 1,000 clinical trials of such treatments are under way, targeting a wide range of different cancers. It is even now possible to reprogram immune cells to fight cancer better by editing their genomes; the first such gene therapy was approved for use in America last month.最令人興奮的是前幾年出現的一種新療法：免疫療法。人類的免疫系統配有一套「剎車」機制，而癌細胞可以踩下這個「剎車」。首個免疫療法實際上是把「剎車」禁用了，好讓白細胞去攻擊腫瘤。該療法還處於初期階段，但在一小部分患者身上，它已經產生了長期的緩解作用，相當於治癒。這類療法正在進行的臨床試驗遠超過1000項，針對的癌症多種多樣。現在甚至可以通過編輯基因組對免疫細胞重新編程，使其更好地抗擊癌症。上個月，首個這類基因療法在美國獲准使用。

Yet cancer sufferers need not wait for the therapies of tomorrow to have a better chance of survival today. Across rich and poor countries, the survivability of cancer varies enormously. Men die at far higher rates than women in some countries; in other countries, at similar levels of development, they do comparably well. The five-year survival rate for a set of three common cancers in America and Canada is above 70%; Germany achieves 64%, whereas Britain manages a mere 52%. Disparities exist within countries, too. America does well in its treatment of cancer overall, but suffers extraordinary inequalities in outcomes. The death rate of black American men from all cancers is 24% higher than it is for white males; breast-cancer death rates among blacks are 42% higher than for whites. A diagnosis in rural America is deadlier than one in its cities.不過，癌症患者不需要等待未來的療法來獲得更大的存活機會。不管是富裕國家還是貧窮國家，國與國之間癌症患者的存活率差別很大。在有些國家，男性患者的死亡率遠高於女性；而在發展水平相似的另一些國家，男女患者的死亡率並無很大差別。在美國和加拿大，三種常見癌症的患者五年存活率高於70%，在德國達到64%，在英國僅為52%。國家內部也存在差異。美國癌症治療方面總體情況較好，但取得的效果非常不均衡。美國黑人男性罹患各種癌症後的死亡率比美國白人男性高24%；黑人乳腺癌的死亡率比白人高42%；鄉村居民的癌症死亡率高於城市居民。

Practical as well as pioneering

Variations between countries are partly a reflection of health-care spending: more than half of patients requiring radiotherapy in low- and middle-income countries do not have access to treatment. But big budgets do not guarantee good outcomes. Iceland and Portugal do not outspend England and Denmark on health care as a proportion of GDP, but past studies show wide variation in survivability in all cancers.

既實用又富開創性

國家之間的差異一定程度上反映了醫療保健支出的差別：在低收入和中等收入國家中，超過一半需要放療的患者沒有接受治療的機會。但是，巨額預算並不能保證良好的結果。冰島和葡萄牙的醫療保健支出佔GDP的比例並不比英國和丹麥高，但過去的研究顯示，這些國家之間各種癌症的存活率差別很大。

Instead, the problem is often how money is spent, not how much of it there is. To take one example, a vaccine exists against the human papillomavirus (HPV), which causes cancers of the cervix in women, as well as cancers of the head and neck. Rwanda started a programme of routine vaccination in 2011, and aims to eradicate cervical cancer by 2020. Other countries are far less systematic. Vaccinations could help prevent cervical cancer in 120,000 Indian women each year.相反，問題往往在於錢是怎麼花的，而不是花了多少錢。舉個例子，人乳頭瘤病毒（HPV）會導致婦女罹患宮頸癌，還會引發頭部和頸部的癌症，現在就出現了一種針對該病毒的疫苗。2011年盧安達啟動了常規疫苗接種計劃，目標是到2020年消滅宮頸癌。其他國家則遠沒有這樣的系統性做法。接種疫苗每年可使12萬印度婦女免於患宮頸癌。

Policymakers are not powerless. More can be done to verify which treatments (and combinations thereof) work best. A ￡1.3bn ($2bn) cancer-drug fund in England, which made expensive new medicines easier to obtain, did not assess the efficacy of the drugs it provided—a huge missed opportunity. Measuring the incidence and survival of cancer, through cancer registries, spotlights where patients are being failed. Access to health care matters, too: the number of Americans whose cancers were diagnosed at the earliest possible opportunity went up after Obamacare was enacted. And prevention remains the best cure of all. Efforts to rein in tobacco use averted 22m deaths (many of them to cancer) between 2008 and 2014. Yet only a tenth of the world』s population lives in countries where taxes make up at least three-quarters of the price of cigarettes, as recommended by the World Health Organisation.政策制定者並非無能為力。他們可以做更多工作來驗證哪種治療方法（及其組合）效果最好。在英國，一個13億英鎊（20億美元）的癌症藥物基金讓人們更容易獲得昂貴的新葯，卻沒有評估所提供藥物的療效，這是一個巨大的錯失的機會。通過癌症病例登記來計算癌症的發病率和存活率，可以找出治療在哪些環節上失敗了。能享受醫保也很重要：奧巴馬醫改實施後，及早診斷出癌症的美國人數量上升了。而預防仍然是最好的解藥。2008年至2014年間，對煙草的控制讓2200萬人免於死亡（其中許多人可能會死於癌症）。然而世界上只有十分之一的人口所在的國家徵收的煙草稅佔到香煙價格的四分之三——這是世界衛生組織推薦的稅率。

Taxes and budgeting are a lot less exciting than tumour-zapping proton beams and antibodies with superpowers. But the decisions of technocrats are as important as the work of technicians. Cancer kills millions of people not simply for want of scientific advance, but also because of bad policy.比起消滅腫瘤的質子束和擁有超能力的抗體，徵稅和編預算要無趣得多。但技術官僚的決策和技術人員的工作一樣重要。癌症奪走了數百萬人的生命不僅是因為缺乏科學進展，糟糕的政策也是原因。