VOA慢速英语2018--医生用脊髓灰质炎治疗脑癌

（单词翻译）

Doctors Treat Brain Cancer With Polio

From VOA Learning English, this is the Health & Lifestyle Report.

Researchers say a virus once feared around the world can help to treat some kinds of cancer in the brain.

The researchers are with the Duke University Health System in the American state of North Carolina. These doctors say they used genetically¹ engineered polio virus to treat people with an aggressive and deadly brain tumor².

The survival rate for people with this form of cancer -- called glioblastoma -- is very low. They usually live no longer than two years after the disease is discovered.

The brain tumors often return after they are treated the first time. The Associated Press notes that John McCain, a well-known member of the United States Senate, is being treated for a recurring⁴ glioblastoma. He was the Republican Party’s candidate for president in 2008.

The study

The Duke University study involved 61 patients. They were chosen for a number of reasons, including the size of their tumor and its position in the brain. Of the 61 patients who got the treatment, 21 percent were alive three years later.

That percentage may seem small. But not when you compare it with another group of brain tumor patients. They were not injected with the polio virus. Only four percent of them were alive three years later.

Annick Desjardins is one of the researchers. She helped to write a report about the study. She said not all patients react to the treatment. However, if they do, they often become long-term survivors⁵.

Stephanie Hopper was a patient in the Duke study. Eight years ago, tests showed she had glioblastoma. She had the tumor removed. But, two years later, it returned.

So, the 27-year old woman joined the Duke study in May of 2012. Doctors injected a genetically engineered version of the polio virus directly into her brain. After this treatment, Hopper's tumor shrunk. In fact, in images of her brain, doctors could hardly see the tumor. And it continues to get smaller. The Associated Press story says that the treatment has given Hopper a chance to finish college and become a medical aide.

Why poliovirus?

The AP story also explains why the doctors chose to use polio virus.

This virus attacks the nervous system and can cause paralysis⁶, making the patient unable to control all or part of the body. The body's natural defenses against disease react very strongly to this attack. So, doctors thought they could use this same response to fight the growth of cancer cells.

Darell Bigner was the lead writer of the report on the study. He explains that by changing the structure of the virus, it loses the ability to affect nerve cells. But the virus still has the ability to kill cancer cells. In fact, the researchers found that the modified virus actually targeted the tumor cells.

"What this did, very simply, was to destroy the ability of the polio virus to infect nerve cells and cause poliomyelitis (polio) any longer. But it retained the ability to kill cancer cells."

The Duke researchers say they are hopeful with this new treatment. So they have started new tests. These tests combine the poliovirus with other approved cancer treatments, such as chemotherapy.

"Those that we've been able to follow long enough have responded to the treatment the second time."

Bigner and his team published their findings in the New England Journal of Medicine.

And that's the Health & Lifestyle report.

I'm Anna Matteo.

Words in This Story

recur³ – v. to happen or appear again

retain – v. to continue to hold (something, such as heat or moisture) as time passes

paralysis – n. medical : a condition in which you are unable to move or feel all or part of your body

poliomyelitis – medical n. : polio

chemotherapy – medical n. : the use of chemicals to treat or control a disease (such as cancer)

modify – v. to change some parts of (something) while not changing other parts