甲狀腺癌“流行”事出有因

An Epidemic of Thyroid Cancer?

甲狀腺癌“流行”事出有因
 

Historically, the science of epidemiology was directed toward identifying and controlling epidemics of infectious disease. In a study just published in the New England Journal of Medicine, my colleagues and I highlight another important job for epidemiologists: identifying and controlling epidemics of medical care.

歷史上，流行病學的研究方向是確診和控制廣泛傳播的傳染病。我和同事們在《新英格蘭醫(yī)學雜志》(New England Journal of Medicine)上剛剛發(fā)表的一篇研究論文中指出，流行病專家還有另外一項任務：識別和控制醫(yī)療界造成的流行病。

The setting is South Korea, where, over the last two decades, the incidence of thyroid cancer has increased fifteenfold. Nowhere in the world is the rate of any cancer growing faster.

研究的背景是韓國。在過去20年里，這里甲狀腺癌的發(fā)病率提高到了最初的15倍。全世界任何地方都沒有哪種癌癥能如此之快地增長。

We’ve all been taught to seek biological explanations for a significant rise in disease — perhaps a new infectious agent or environmental exposure. But in South Korea, we are seeing something different: an epidemic of diagnosis.

我們受過的教育都是，為發(fā)病率的顯著提高尋找生物學上的解釋，或許是新的病原體，或許是環(huán)境暴露。然而在韓國，我們看到了不同的情況，這種流行病是因為診斷造成的。

In 1999 the government initiated a national health-screening program focused on reducing cancer and other common diseases. Although thyroid cancer screening was not included in the program, all it requires is a simple test — an ultrasound of the neck. Hospitals have ultrasound machines and so do many doctors’ offices. Both promoted thyroid cancer screening as an inexpensive add-on to the government program. It was an easy sell, particularly with the government, the medical community, the news media and cancer “survivors” praising the virtue of early cancer detection.

1999年，韓國政府啟動了一項全國性的體檢計劃，主要目的是減少癌癥和常見病。盡管其中并不包括甲狀腺癌篩查，但它只需要一個簡單的步驟：頸部超聲波檢查。醫(yī)院里有超聲波設備，很多醫(yī)生的診所里也有。醫(yī)院和醫(yī)生都認為，它是政府計劃之外一項廉價的補充檢查，因而鼓勵患者檢查。而患者也很樂于接受，尤其是因為政府、醫(yī)療界、新聞媒體和癌癥“生還者”都稱贊，及早發(fā)現癌癥有好處。

In doing so they inadvertently highlighted the major harm of early detection: What was a rare cancer is now the most common cancer in South Korea.

但這樣做也意外地突顯了及早診斷的巨大危害：一種本來罕見的癌癥，成為了韓國最常見的癌癥。

Where did all those new thyroid cancers come from? They were always there. As early as 1947 pathologists recognized that, although it was a very rare cause of death, thyroid cancer was a frequent finding during autopsies. Studies have since shown that over a third of adults have thyroid cancer. Virtually all of these cancers are small “papillary thyroid cancers,” many of which will never become evident during a person’s life.

那些新增的甲狀腺癌患者是從哪里來的呢?他們其實一直存在。早在1947年，病理學家就發(fā)現，盡管極少成為死因，但是在尸檢中經常發(fā)現死者患有甲狀腺癌的情況。從那時起，研究就發(fā)現，超過三分之一的成年人患有甲狀腺癌。其中幾乎所有人患的都是微小的“甲狀腺乳頭狀癌”，許多人一生中癥狀都不明顯。

Unless that person receives a screening ultrasound. In fact, virtually all the newly identified thyroid cancers in Korea are papillary thyroid cancers. How do we know this is not a real epidemic of disease? Because the number of Koreans dying from thyroid cancer has not changed. If the screening were saving lives, the death rate would decline, or increase more slowly as the epidemic spread — but not stay perfectly flat.

除非這個人接受了超聲波檢查。事實上在韓國，幾乎所有新確診的甲狀腺癌都是乳頭狀癌。我們怎么才能知道這不是真正的流行病呢?因為在韓國，死于甲狀腺癌的人數并沒有變化。如果超聲檢查挽救了患者的生命，那么死亡率應該降低才對，而如果流行病蔓延開來，死亡率應該緩慢上升才對——然而數據卻完全沒有起伏。

An epidemic of diagnosis is not good for anyone’s health. Resources are needlessly diverted; people are needlessly scared. But the biggest problem is that it begets an epidemic of treatment.

診斷呈現的流行病對任何人的健康都沒有好處，而且它毫無必要地轉移了資源，也毫無必要地驚嚇了患者。然而最大的問題是，它在醫(yī)療體系內催生了過度治療。

The majority of patients given diagnoses of thyroid cancer have their thyroid gland removed. The thyroid is an important gland — it produces the hormones that control metabolism. Without it, patients may need lifelong thyroid replacement therapy. And it can take doctors a while to find the right dose for each individual. In the meantime, patients suffer from the effects of too little or too much thyroid hormone, including energy and weight fluctuations.

多數被診斷患有甲狀腺癌的患者，被切除了甲狀腺。然而甲狀腺是一個重要的腺體，它能分泌控制新陳代謝的激素。如果切除了，患者就可能會終生需要甲狀腺替代治療，而且醫(yī)生可能需要一段時間才能為每一位患者找到恰當的劑量。與此同時，患者還要承受甲狀腺素水平過低或過高的后果，包括精力和體重的波動。

The surgery has other less common complications. In South Korea and the United States about 10 percent of patients have problems with calcium metabolism and about 2 percent experience vocal cord paralysis. And, as with any surgery, there can be life-threatening effects — blood clots in the lungs, heart attacks and strokes. In about two of every 1,000 thyroid cancer operations, the patient dies. It’s rare, but it happens.

這種手術也會產生一些并不十分常見的并發(fā)癥。在韓國和美國，大約10%的患者產生了鈣質代謝問題，約有2%的患者發(fā)生了聲帶麻痹。此外，就像任何一種手術一樣，它可能會產生威脅生命的后果，如肺部血凝塊、心肌梗死和中風。每一千例甲狀腺癌手術中，大約會有兩名患者身亡。很罕見，但的確會發(fā)生。

Could what happened in South Korea happen here? Absolutely. Even without a concerted effort to promote screening, thyroid cancer incidence in the United States is up threefold since 1975. To reverse this trend, we need to actively discourage early thyroid cancer detection.

在韓國發(fā)生的情況也會在美國發(fā)生嗎?絕對會。盡管沒有各方同心協力推動篩查，美國的甲狀腺病例自1975年以來也已經提高到了最初的三倍。要想扭轉這種趨勢，我們需要積極地勸阻甲狀腺癌的早期檢查。

The virtue of early detection is so ingrained and so appealing that many assume that screening can only be good for you. But that’s not true. The Korean experience illustrates the downside of trying to find cancer early: overdiagnosis and overtreatment. The problem is greatest for thyroid and prostate cancer, but also exists for cancers of the lung, breast, skin and kidney. And then there is all the angst surrounding screening — that can’t be good for anyone’s health.

及早檢查有好處的觀念根深蒂固，而且也很吸引人，所以許多人都認為，做一下檢查只會有好處。然而事實并非如此。韓國的經驗顯示出，試圖早期診斷癌癥的做法有負面的影響：過度診斷和過度治療。甲狀腺癌和前列腺癌的問題最為嚴重，然而對肺癌、乳腺癌、皮膚癌、腎癌也存在。當然還有對于檢查的焦躁，這可是對任何人的健康都不會有好處的。

Of course, screening makes sense in some situations: in particular for people who are at a genuinely high risk for the cancer — those with multiple cancer deaths in their family history. People at average risk who expect to live long enough to experience the potential benefit in the future — and who are willing to accept the chance of harm from unneeded treatment now — may also decide that the screening makes sense for them.

當然，檢查在一些情況下是有意義的，尤其是癌癥真正的高?；颊撸杭易鍍扔卸嗳怂烙诎┌Y的患者。患病風險中等，但預期壽命足夠長，未來可以體驗到潛在收益的人——以及那些愿意接受現在并不需要的治療帶來的受到損害的可能性的人——或許也會認定接受檢查是合理的。