2015年考研暑假必读文章:Cancer and Staying Fit

来源:新东方 2019-01-21

Cancer and Staying Fit

Four times a week, Anne Rinn, 28, a psychology professor in Bowling Green, Ky., whose mother died of breast cancer, goes to kickboxing, aerobics or Pilates classes. Liz Usborne, a 64-year-old breast-cancer survivor, lobs tennis balls over the net and circuit-trains at a women's gym near her home in Bonita, Cafif. The thread binding them? Concern about getting-or surviving and thriving after--breast cancer.

The American Cancer Society estimates that this year, 241,000 women will learn they have breast cancer and 40,000 women will die of it. Fortunately , a growing list of effective therapies developed during the past decade has helped extend lives, one reason that deaths from breast cancer have been dropping slowly since 1990. Living among us are more than 2 million women who have undergone breast-cancer treatments.

Modern miracle drugs like Tamoxifen and Raloxifene routinely cut risk for breast cancer in women whose medical histories or genes make them especially vulnerable to it. But reams of research also suggest that exercise--an activity as old as the human race-substantially reduces the odds of ever getting the disease, lengthens survival and considerably enhances quality of life for women with breast cancer.

Scientists don't completely understand why exercise is so important, but they're actively looking for answers. Roughly two thirds of all breast cancers are considered estrogen-positive; that means that the hormone estrogen fuels their growth. The rest are estrogen-negative. Many experts believe regular exercise lowers the amount of estrogen circulating through the body in the bloodstream. So for certain types of breast cancer, less estrogen equals less fuel. Exercise also pares off hormonally active fat tissue. Fat manufactures substance called Aromatase that converts hormones known as androgens to estrogen. After menopause, when the ovaries stop cranking out high levels of estrogen, this hormonal cascade becomes the major source of estrogen in a woman's body

Recently two large, carefully designed studies suggested exercise may work through more than just hormonal mechanisms linked to estrogen. In a study published last month in the Archives of Internal Medicine, researchers speculated that exercise might affect tumor aggressiveness. The researchers found that long-term moderate or strenuous activity over a lifetime cut risk for developing estrogen-negative invasive breast cancers (though not estrogen-positive cancers). Since fewer therapies are effective against estrogen-negative cancers, that's heartening news. Some earlier research on exercise suggests it lowers risk for estrogen-positive cancers, too. Scientists are also looking beyond estrogen at the effects exercise has on insulin, leptin and certain growth factors.

Regular exercise early in life, particularly around puberty, and exercise vigorous enough to suppress other reproductive hormones may make a difference, too. A 2005 multicenter study on lifetime activity matched more than 4,000 white and black breast-cancer survivors with controls. Researchers found a 20 percent decrease in breast-cancer risk for the most versus least active women.

After a woman is diagnosed, exercise can dramatically lengthen survival and lower the odds of another tumor. For up to 14 years, the Nurses' Health Study tracked nearly 3,000 participants diagnosed with breast cancer. Researchers found that recurrence rates and deaths from breast cancer (and from all causes) dipped 26 to 40 percent among those who exercised most, compared with their sedentary peers. Brisk walking or equivalent energy-burning activity for three to five hours a week-about 30 minutes a day-netted the biggest benefits. But even being active for one to three hours a week reduced risk to some degree

Excess pounds lower the likelihood of survival after breast cancer. But for many women, maintaining a healthy weight is often a struggle, especially during treatment. Chemotherapy or radiation can make women feel too tired to exercise. Steroids given to help ease certain side effects of chemotherapy prompt a ravenous appetite. Nausea can lead to almost continuous nibbling of comfort foods to settle queasy stomachs. Some anticancer medications that work by tampering with hormones may have a hand in weight gain, too. One such hormonal drug is Tamoxifen, which keeps estrogen from entering breast cells by blocking receptors atop the cells that allow access. Studies have yet to confirm a connection, but many women on Tamoxifen complain of watching the scale inch upward. No matter what the root cause is for weight gain, exercise of all sorts helps burn calories. And paradoxically, for those who feel too wiped out to fit exercise in, some evidence shows light to moderate activities may actually alleviate treatment-induced fatigue

Doctors once believed upper-body resistance training was apt to trigger the chronic swelling and discomfort of Lymphedema in women treated for breast cancer. Lymph is a thin, milky fluid that collects in spaces between cells. Carrying germ-battling immune cells, it seeps through a lacy network of channels in the body before draining into the circulatory system. Lymphedema occurs when lymph backs up, often in an arm or sometimes in the torso, after surgery or radiation alters lymph channels. Several recent studies suggest that a gradual approach and proper precautions make resistance training unlikely to raise the risk of developing Lymphedema or worsening it if it already exists.

That's important news. Resistance training helps reverse the muscle loss and fat gain called Sarcopenia that often follows chemo-therapy and hormonal therapy. It?s helpful in other ways, too. Osteoporosis, which sets the stage for life-altering bone fractures, may be hastened by certain anticancer treatments. Chemo-therapy, for example, sometimes pushes women into early menopause by pre-maturely shutting down their ovaries. Since estrogen helps protects bones, losing it speeds bone-thinning, particularly in the spine and hips, which are especially vulnerable to fractures. Also known to contribute to osteoporosis is a class of breast-cancer drugs called aromatase inhibitors that cut off the most plentiful supply of estrogen after menopause by interrupting the process that converts androgens into estrogen. Resistance training slows bone loss and may even strengthen bones.

Quality of life counts, too. In clinical trials, moderate to vigorous exercise programs notched up progressively to 45-minute sessions at least three times a week eased anxiety and depression, enhanced mood and self-esteem, and helped counter fatigue.

Thus far, there are few studies of exercise in women with advanced breast cancer, although early evidence suggests that physical activity offers benefits here, too, such as less fatigue. More rigorous studies investigating links between breast cancer and exercise are underway. Dont settle back to await developments, though. Rise from your reading and head out for a walk.

#p#副标题#e#

重点单词
therapy 
[中文释义]n.疗法,治疗
[大纲全义]n.治疗,疗法,(不需要药物或手术的)物理疗法

treatment
[中文释义]n.治疗
[大纲全义]n.治疗,疗法;讨待;待遇;处理;论述

vulnerable 
[中文释义] adj.易受伤害的
[大纲全义]adj.易受攻击的;易受伤的,脆弱的

roughly 
[中文释义] adv概略地
[大纲全义] adv粗糙地;毛糙地

speculate 
[中文释义] v.推测
[大纲全义] v.思索;推测;投机

tumor 
[中文释义] n.肿块
[大纲全义] n.(肿)瘤.肿块

moderate 
[中文释义] adj.适度的
[大纲全义] adj.有节制的;中等的;适度的;温和的;穗健的;合理的v缓和;使适中;审核(评分)
n.持温和观点者(尤指政见)

strenuous 
[中文释义] adj.高强度的
[大纲全义]adj.费力的;繁重的;奋发的;顽强的

negative 
[中文释义] adj阴性的
[大纲全义] adj.否定的,消极的,阴性的n.负数;(摄影)底片,负片

heartening
[中文释义]adj.振奋人心的
[大纲全义]adj.振奋人心的

vigorous 
[中文释义]adj.精力充沛的
[大纲全义]adj.朝气蓬勃的,精力旺盛的;有力的

reproductive
[中文释义]adj.生殖的
[大纲全义]adj.复制的,生殖的

versus 
[中文释义]adj.相时比
[大纲全义]prep.(vs.)......对......(在诉讼,比赛等);与......相对

超纲单词
estrogen n.雌激素 hormonally adv.荷尔蒙的
androgen n.男性荷尔蒙 menopause n.停经期
ovary n.卵巢 cascade n.大量
invasive adj.侵略性的 insulin n.腹岛素
puberty n.青春期

重点段落译文
据美国癌症协会预计,今年将有24100名女性得知她们患有乳腺癌,另外还有4万名女性将死于这种癌症。幸运的是,在过去十年里人们研发了越来越有效的治疗方法来帮助人们延长寿命,这使得自1990年以来死于乳腺癌的人数已经开始逐渐减少。生活在我们周围的女性中有200多万名妇女曾接受乳腺癌治疗。

有些女性的病史或基因使她们特别容易患上乳腺癌,但现代的灵丹妙药如他莫昔芬和雷洛昔芬则可以降低这些女性患乳腺癌的风险。同时大量的研究表明体育锻炼—同人类一样古老的运动可以从本质上降低女性患上乳腺癌的几率,延长女性寿命以及从很大程度上提高患乳腺癌妇女的生活质量。

科学家并不完全明白为什么体育锻炼如此有效,但他们正积极地寻找答案。经诊断,大约有三分之二的乳腺癌患者雌性激素呈阳性,这就意味着荷尔蒙雌激素会导致病况的恶化,其余患者的雌性激素均呈阴性。许多专家相信经常运动可以降低体内血管中雌激素的循环量,所以对于某些类型的乳腺癌患者而言减少雌性激素等于减少恶化。同时运动还可以减少激素活跃的脂肪组织。由脂肪产生的一种叫做芳香化酶的物质可以将雄性激素转换为雌性激素。绝经后,当卵巢停止分泌大量的雌性激素时,这种激素大量转换就成为女性体内主要的雌性激素来源。

最近两个精心设计的大型研究表明,体育锻炼或许不仅仅只在与雌激素相关联的荷尔蒙机能上起作用。在上个月发表在《内科医学档案》上的一项研究中,研究人员推测运动可能会影响肿瘤的侵害。此外研究者们还发现长期进行中强度或高强度的活动可以降低患雌激素呈阴性的乳腺癌的风险(虽然不是雌性激素呈阳性的癌症)。由于可以有效地治疗雌激素呈阴性乳腺癌的方案很少,所以这可真是一个振奋人心的消息。早期针对运动的一些研究表明,锻炼也可以降低雌激素呈阳性乳腺癌的几率。科学家们正在研究运动对雌性激素之外的胰岛素、瘦素和某些生长激素的作用。

早期,特别是青春期的规律性锻炼和足以抑制生长激素生长的充沛运动也可以改善乳腺癌得病率。2005年,一项关于终身锻炼的多通道研究,把四千多名白种人和黑种人的乳腺癌幸存者与控制力相联系。研究人员发现,参加运动最多的女性比参加运动最少的女性患乳腺癌的几率减少了20%。




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