每天一篇经济学人 | Breast cancer 乳腺癌（2022年第87...

October is breast cancer awareness month, and thankfully it seems quite a few Americans are aware of it. Mortality from breast cancer has dropped by 43% over the past 30 years, according to a new report by the American Cancer Society (acs). This is largely thanks to earlier detection and better treatments. All told, the improvement adds up to 460,000 lives saved over the past three decades.

10月是乳腺癌宣传月，值得庆幸的是，似乎相当多的美国人意识到了这一点。根据美国癌症协会的一份新报告，乳腺癌的死亡率在过去30年下降了43%。这在很大程度上要归功于更早的发现以及更好的治疗。总的来说，在过去的30年里，这些改善挽救了46万人的生命。

Most public-health news from America is gloomy. About 100,000 people die each year from drug overdoses. Life expectancy, which used to creep steadily up year after year, has gone into reverse: America is unusual among rich countries in that life expectancy has fallen back to a level it was last at in the mid-1990s. Within that overall picture though, there have been improvements. Breast cancer joins lung cancer, the most prevalent cause of death from cancer, colorectal, and prostate cancer in becoming less lethal over the past three decades. Since deaths avoided tend to be rather neglected relative to deaths caused, it is worth considering what has gone right.

大多数来自美国的公共卫生新闻都令人沮丧。每年大约有10万人死于药物过量。曾经年复一年稳步增长的预期寿命已经开始逆转:在发达国家中，美国的预期寿命已经回落到上世纪90年代中期的水平，这是不寻常的。不过，在整体情况下，情况有所改善。在过去的30年里，乳腺癌与肺癌(最常见的导致死亡的癌症)、结肠直肠癌和前列腺癌一起变得不那么致命。由于与造成的死亡相比，避免的死亡往往被忽视，因此值得考虑哪些是正确的。

According to the Centres for Disease Control and Prevention, about 264,000 cases of breast cancer are diagnosed among American women each year, and about 42,000 women die. Men are susceptible too, though male breast cancer is very rare: each year about 2,400 men are diagnosed with breast cancer and 500 die. Early diagnosis is key to survival. Today someone diagnosed with breast cancer that has not spread to any other body part has a 99% chance of living for at least five more years. That compares with 29% for breast cancer that has spread throughout the body. 

根据美国疾病控制与预防中心的数据，美国女性中每年约有26.4万例乳腺癌确诊病例，其中约4.2万例死亡。男性也易受影响，尽管男性乳腺癌非常罕见: 每年约有2400名男性被诊断患有乳腺癌，其中500人死亡。早期诊断是生存的关键。今天，被诊断患有乳腺癌但没有扩散到身体其他部位的人至少有99%的机会再活5年。相比之下，扩散到全身的乳腺癌的这一比例为29%。

How has this improvement come about? Three-quarters of women with health insurance have regular mammograms, which result in earlier detection. Treatments have also become more targeted. Doctors are now able to divide breast cancer diagnoses into subtypes based on whether the cancer contains oestrogen and progesterone receptors, which means they are sensitive to hormones, and whether they have high levels of her2 protein, which stimulates cell growth. These classifications allow for more specific, and therefore effective, treatment.

这种改善是如何产生的? 有医疗保险的女性中，有四分之三定期进行乳房x光检查，这样可以更早发现。治疗也变得更有针对性。医生现在可以根据癌症是否含有雌激素和孕激素受体(这意味着它们对激素敏感)，以及是否有高水平的HER2蛋白(刺激细胞生长)，将乳腺癌诊断分为亚型。这些分类允许更具体的，因此有效的治疗。

While mortality rates have decreased, the prevalence of breast cancer has risen in the past 40 years—and not just because more people are being screened. The increase is probably due to high obesity rates and declining fertility among women, says Rebecca Siegel, an author of the acs report. Breast cancer and obesity are linked because fat cells synthesise oestrogen production in post-menopausal women, and higher oestrogen levels are associated with breast cancer. As for fertility, having children at a later age and not having children at all is associated with increased risk of breast cancer. “It’s not fully understood why, but it’s thought to be related to exposure to oestrogen,” says Ms Siegel.

虽然死亡率下降了，但在过去的40年里，乳腺癌的患病率却上升了，不仅仅是因为更多的人接受了筛查。美国癌症学会报告的作者丽贝卡·西格尔称，乳腺癌患病率的增加可能是由于女性的高肥胖率和生育率的下降。乳腺癌和肥胖是有关联的，因为在绝经后的女性中，脂肪细胞会合成雌激素，而雌激素水平较高与乳腺癌有关。至于生育能力，晚育和不生育都与患乳腺癌的风险增加有关。西格尔女士称:“ 原因还不完全清楚，但人们认为这与暴露于雌激素有关。”

Still, the news is mostly good. As ever there are racial gaps in outcomes, and people without health insurance are much less likely to get a mammogram. But with the exception of Native Americans, all racial groups have seen mortality rates from breast cancer decline.

尽管如此，大部分消息还是好的。结果一如既往地存在种族差异，没有医保的人做乳房x光检查的可能性要小得多。但除了印第安人，所有种族的乳腺癌死亡率都在下降。