双语阅读:只要抽一次血,50多种癌症都可以提前几年预测到

验血可以检测出50种不同类型的癌症

翻译:涂博士(微信号:jefftu95)

通过一项新的血液检查,50多种癌症以及其病灶的具体位置都可以在症状发作之前提前检测出来。

美国和英国的研究人员开发了这项新测试,并且在《肿瘤学年鉴》(Annals of Oncology)上发布了他们的发现。

通常,医生只能在病人出现症状后才能做出诊断,但这时对于治好癌症来说可能已经太晚了,所以医生迫切需要更好的癌症诊断工具。

现在已经有一些筛查项目(例如乳腺癌的乳房X线照片和宫颈癌的子宫颈抹片检查),旨在通过在早期阶段检测癌症来克服这个问题。

但是,这些检测局限于少数癌症,通常仅适用于一部分人群(风险最高的人群),并且参检率大小不一。由于这些检测方法具有侵入性或引起不适感,也会让一些人不愿意去做筛查。

现在,研究人员已经开发出一种简单的血液测试,只要抽一次血就检测出50多种不同类型的癌症。在许多种情况下,能够在病人出现任何临床体征或症状之前就诊断出病症。

生物学与机器学习的结合

肿瘤细胞会释放一种被称为无细胞DNA(cfDNA)的DNA到血液里,这个新的检测方法就是在血液里找到这种DNA。然而,由于许多其他细胞也会将DNA释放到血液中,要从中检测到具有肿瘤特异性的cfDNA非常有挑战性。

该测试通过检测DNA的变化来检测特定于癌细胞的DNA。这个DNA变化就是多了一种称为甲基的化学物质,该化学物质与肿瘤的生长有关。

医护专业人员从血液样本中分离出cfDNA并对其进行测序,找到甲基化的部分后,将结果输入计算机,就可以识别来自癌细胞和非癌细胞的DNA。

然后计算机就可以预测一个人是否患有癌症,甚至预测出癌症的可能类型。

93%的准确率

这项研究是对一项对15,000人进行的大型研究的一部分,该试验对4,000多人的血液进行了测试,其中大约一半患有癌症。这项研究含括了50多种癌症。

该项研究在93%的样本中得到了准确的测试结果,并且在96%的样本中可以准确预测癌症病灶会在身体哪个位置出现。

假阳性率仅为0.7%,这意味着只有不到1%的人在使用此测试会误诊为癌症。

与乳腺癌筛查程序(假阳性率约为10%)相比,这种新方法的好处是显而易见的。

资深研究作者迈克尔·塞登(Michael Seiden)博士表示希望将来有一天在全国性筛查项目中可以使用该项测试。

他说:“我们认为,在全民筛查中使用多癌症早期血液检测必须要满足一些基本要求,而这些数据表明,这种有针对性的甲基化测试满足了这些基本要求。”

他解释说,这些要求是“具有通过极低的假阳性率进行一次检测多种致命癌症类型的能力,以及能够以高准确度识别癌症病灶在体内的位置的能力。这些能力可以帮助医护人员决定下一步的诊断和护理。”

难检测的癌症的新希望

研究人员仍在对更大的人群进行研究以验证这项研究的结果。尽管这些试验的结果尚未确定,但科学家们对其充满了希望。

正如《肿瘤学年鉴》(Annals of Oncology)的主编Fabrice André教授所解释的那样:

“这是一项具有里程碑意义的研究,也是开发易于执行的筛选工具的第一步。尽早发现超过50%的癌症,每年可以在全球范围内挽救数百万人的生命,并可以大大降低积极治疗引起的发病率。”

科学家特别希望该测试将有助于诊断那些症状很晚才出现的癌症,以及医生通常在晚期才能够诊断的癌症。

这项研究包含了12种最危险的癌症,包括胰腺癌,肺癌和卵巢癌,这些癌症在美国每年占所有与癌症相关的死亡人数的60%以上。

当前,大多数癌症尚无办法在症状发展之前被筛查出来。但是,这项血液检查可以准确地检测出其中67%以上的癌症。

在开始阅读英文原文之前,请先复习下列核心词汇​:

blood - n. 血液
detect - v. 检测,发现
different - adj. 不同的
cancer - n. 癌症
originate - v. 起源于
symptom - n. 症状
Annals of Oncology - 肿瘤学年鉴
journal - n. 杂志
urgent - adj. 紧急的
diagnostic - adj. 诊断的
false - adj. 假的
screen - v. 筛选,n. 显示屏
mammogram - 乳房X线照片
breast - n. 胸,乳房
cervical - adj. 颈部的,子宫颈的
overcome - v. 克服
clinical - adj. 临床的
invasive - adj. 侵入性的
uncomfortable - adj. 不舒服的
discourage - v. 阻碍,挫伤
biology - n. 生物学
landmark - n. 里程碑
reduce - v. 减少
morbidity - n. 发病率
induce - v. 导致
aggressive - adj. 侵略的,好斗的
treatment - n. 治疗
tumor - n. 肿瘤
population-level - 相当大的人群(population指的是人口,population-level指的是人群数量达到人口统计的级别了,就是相当大的人群的意思)

在复习了以上词汇后,请将下面的英文原文一口气读完,不要在中途停下来去查那些不认识的单词。有了上面的核心单词打底,你完全可以将整篇文章读完并且理解里面的大致意思。记住,你只要做到大致明白就可以了。

阅读能力和阅读量成正比,要提高阅读量,必须是大量的泛读,如果要对每个不懂的单词都去查字典,那么就不可能通过大量的泛读来提高你的阅读量。

如果你对某篇泛读文章特别喜欢,可以在泛读一遍以后再慢慢地精读。如果在精读的过程中对某些句子不是太明白需要讲解,或者你希望以后多看到哪方面的双语阅读,欢迎联系涂博士(微信号:jefftu95)。

Blood test can detect 50 different types of cancer

Written by Eleanor Bird, M.S. on April 9, 2020
Fact checked by Jasmin Collier

Medical News Today

A new blood test can detect more than 50 types of cancer, as well as where in the body they originated — even before symptoms develop.

Researchers in the United States and United Kingdom developed the new test, and they now report their findings in the journal Annals of Oncology.

There is an urgent need for better diagnostic tools for cancer. All too often, healthcare professionals can only make a diagnosis after symptoms have developed — at which point it may be too late for curative treatment.

Screening programs, such as mammograms for breast cancer and Pap smears for cervical cancer, intend to overcome this problem by detecting cancer at an earlier stage.

However, these tests are typically only available to a subset of the population (those at highest risk), are limited to a small number of cancers, and have variable rates of compliance. These methods can also be invasive or uncomfortable, which may discourage attendance.

Now, researchers have developed a simple blood test that can detect over 50 different types of cancer, in many cases before any clinical signs or symptoms develop, from just a single draw of blood.

Biology meets machine learning

The test works using a type of DNA released by tumor cells. This sheds into the blood, where it is known as cell-free DNA (cfDNA). It can be challenging to identify tumor-specific cfDNA, however, because many other cells also release DNA into the blood.

This test detects DNA that is specifically from cancer cells using changes to the DNA — namely, the addition of a chemical called a methyl group, which is associated with tumor growth.

After isolating cfDNA from the blood sample and sequencing it to find the methylated parts, healthcare professionals can feed the results into a computer that can recognize DNA from cancer and noncancer cells.

The computer can then predict whether or not a person has cancer, and even what type it might be.

93% accuracy

The study — which is part of a larger study of 15,000 people — tested the blood of more than 4,000 people, roughly half of whom had cancer. The researchers included over 50 types of cancer in the study.

The test was accurate in 93% of the samples and could accurately predict where in the body the cancer first developed in 96% of the samples.

The false positive rate was just 0.7%, which means that less than 1% of people would have an inaccurate diagnosis of cancer using this test.

Compared with breast cancer screening programs, which have a false positive rate of around 10%, the benefits of this new approach are clear.

Senior study author Dr. Michael Seiden hopes that national screening programs could one day use the test.

“These data,” he says, “support the ability of this targeted methylation test to meet what we believe are the fundamental requirements for a multi-cancer early detection blood test that could be used for population-level screening.”

These requirements, he explains, are the “ability to detect multiple deadly cancer types with a single test that has a very low false positive rate, and the ability to identify where in the body the cancer is located with high accuracy to help healthcare providers to direct next steps for diagnosis and care.”

Hope for hard-to-detect cancers

Researchers are still validating the test in larger, population-level studies. Although the results of these trials are pending, scientists are extremely hopeful.

As Prof. Fabrice André, editor-in-chief of Annals of Oncology, explains:

“This is a landmark study and a first step toward the development of easy-to-perform screening tools. Earlier detection of more than 50% of cancers could save millions of lives every year worldwide and could dramatically reduce morbidity induced by aggressive treatments.”

Scientists are particularly hopeful that the test will help diagnose cancers wherein symptoms do not develop for a long time and those that doctors are not usually able to diagnose until a later stage.

The study looked at 12 of the most dangerous types of cancer, including pancreatic, lung, and ovarian cancers, which account for over 60% of all cancer-related deaths every year in the U.S.

Currently, there is no way to screen for most of these cancers before symptoms develop. However, this blood test accurately detected more than 67% of them.

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