Doctors Have a New Tool to Identify Breast Cancer
Breast cancer is the most common cancer in women worldwide.
Early discovery and treatment can save lives.
Scientists are working new ways to recognize breast cancer while at the same time studying existing methods of identification to find out what is best.
Take mammograms, for example. During the test, a technician takes an X-ray picture of a woman's breast as it is pressed between two glass plates. A radiologist then examines the image for signs of cancer.
Mammograms are the best tools available for recognizing the disease. The number of breast cancer deaths has fallen by 30 percent in the United States since doctors began offering mammography in the 1970s. The reason: the chances of beating cancer are higher when the disease is found early.
Yet mammograms are not perfect. A mammogram can look normal even when cancer is present. It can also look abnormal, or unusual, when cancer is not present.
Traditional mammograms are two dimensional (2-D). They show length and width. But for the 40 to 50 percent of women with dense breasts, it is difficult for radiologists to see cancer on 2-D images.
Three-dimensional mammograms provide a more detailed look. So women with dense breasts may get better results from a 3-D mammogram, said Otis Brawley of the American Cancer Society.
"It might find disease that we need to find that two-dimensional does not," Brawley said. He added that 3-D testing costs more and involves higher levels of radiation. It also is not 100 % perfect, he said.
Cost aside, one study involving 13 U.S. hospitals showed that 3-D mammograms recognized an additional 40 percent of invasive cancers.
For better results, a woman could have a whole-breast ultrasound. This test requires the patient to lie on her back as the ultrasound device slowly moves back and forth. The exam captures between 3,000 and 5,000 images of the breast.
Megha Garg is the director of the breast-imaging program at the University of Missouri cancer center. She says the whole-breast ultrasound "helps detect additional breast cancers in females who have dense breasts."
The ultrasound doesn't use radiation, so it is less risky than a mammogram. But Garg says the traditional mammogram remains a helpful tool because it is very effective.
Researchers are studying which method is best at detecting cancer.
North America, Western Europe and Australia have the highest rates of breast cancer. Yet the World Health Organization reports that almost 50 percent of the cases and nearly 60 percent of the deaths happen in less-developed countries.
With improvements, nearly 400,000 women's lives could be saved every year.
I'm Susan Shand.
1.find out 发现
I need to find out who tried to frame me.
2.breast cancer 乳腺癌
She had localized breast cancer and both of her doctors had advised surgery.
3.moves back 退缩
The huntsman cannot help but moves back, surprised and useless.
4.invasive cancers 浸润性癌症
Invasive cancers such as IDC are more serious and account for70-80 percent of all breast cancers.
5.Scientists are working new ways to recognize breast cancer while at the same time studying existing methods of identification to find out what is best.
at the same time 同时
It's impossible to get everybody together at the same time.
We can't hold the two meetings at the same time; we must stagger them.
6.Mammograms are the best tools available for recognizing the disease.
be available for 可用的；有效的
Mr Leach is on holiday and was not available for comment.
Fishing tackle is available for hire.
以乳房X光检查为例 。医师在检查过程中会拍摄女性乳房的X光片，然后交由放射科医生检查是否患有癌症 。
乳房X光检查是筛查乳腺癌的最佳工具 。自上世纪70年代医生开始利用乳房X光检查后，美国乳腺癌死亡人数下降了30% 。原因是：越早发现癌症，其治愈率越高 。
不过，乳房X光检查并非万能 。有时候患有癌症，X光片可能会显示正常 。而有的病人并未患乳腺癌，X光片可能也会显示异常 。
传统的乳房X光检查是二维的（2-D） 。只会显示长度与宽度 。而对于40%到50%致密型乳腺女性来说，放射科医生很难在二维图像上发现癌症迹象 。
三维乳房X光检查可以提供更详细的影像 。美国癌症学会的奥蒂斯·布劳利（Otis Brawley）表示，致密型乳腺的女性接受三维乳房X光检查可能会获得更精准的筛选结果 。
布劳利表示：“三维乳房X光检查能帮助医生发现二维检查所甄别不了的疾病 。”他还指出，三维乳房X光检查成本更高，辐射程度也更高 。这种方式也称不上绝对完美 。
为了获得更好的筛查效果，女性可以进行乳房整体超声检查 。检查时，病人需仰卧让超声装置缓慢地来回移动 。这种检查将拍摄3000到5000张乳房的图像 。
梅加·加格（Megha Garg）是密苏里大学癌症中心乳腺成像项目主任 。她表示，乳腺整体超声检查“有助于帮致密型乳腺女性筛查出更多的乳腺癌 。”
这种超声检查没有辐射，因此风险低于X光检查 。但是加格表示，传统X光检查仍然是一项有用的工具，因为它十分有效 。
北美、西欧和澳大利亚的乳腺癌发病率最高 。然而，世界卫生组织报告称，近50%的病例和近60%的死亡案例均发生在欠发达国家 。