肺癌

也许读者都熟悉身体肥胖、体重过重、患肥胖症，会导致心血管疾病。但是肥胖跟癌症有关系吗？恐怕多数人会摇头。
身体的肥胖度、体重过重与癌症的关系
世界癌症基金会2007年的专家报告关于预防癌症的建议一，是尽量降低体重到标准体重水平，不要过重，过胖，而且要从儿童时期做起。通过检验有关的实验报告文献，这个报告列举了6种癌症，认为与身体肥胖和过重有关，而且说这两者的关系是convincing（确信的）。肥胖包括两种，一是整体肥胖，与6种癌症有关，它们是
1）食道癌
2）子宫内膜癌
3）胰腺癌
4）结肠癌
5）乳腺癌（更年期之后）
6）肾脏癌
另一是腹部肥胖，与结肠癌有关。
你可能觉得有点匪夷所思，肥胖好像没有那么大危害性吧？
在肯定的程度上，这个报告采用三级评价，第一级是convincing(确信的)；第二级是probable(很可能的)；第三级是limited suggestive(有限提示的)。限于篇幅，我们主要关注属于第一级的评价。上述6种癌症跟身体肥胖有关，被评价为结论确信级。关于评价论证的方法，例如如何采用Forest Plot 图，如何分析统计上的可信度，如何进行会议评议，限于篇幅这里就只能略去不谈。读者有兴趣可以自己阅读原文。

需要解说的应该是这个说法背后的道理。这个报告主要引用两个文献，一是2003年Hursting等人的论文《热量限制、衰老、癌症预防（Calorie, Aging, and Cancer Prevention）》和2004年Calle EE等人的论文《体重过重、肥胖症与癌症（Overweight, Obesity and Cancer）》，对于肥胖背后的促癌机制，有如下的解释。

1）肥胖影响人体胰岛素样因子IGF-1、胰岛素、瘦素。
它们在肥胖人群体内的水平升高，能促进癌细胞的生长。腹部肥胖尤其造成胰岛素抵抗增
加，使胰腺补偿作用增加胰岛素生产。结果增加了结肠和子宫内膜癌症的风险。还可能增加肾脏癌的风险。肥胖者的循环瘦素(Leptin) 高，跟结肠癌和前列腺癌有关。

2）肥胖影响类固醇激素。
雌激素、雄激素、孕酮很可能在肥胖与癌症中起作用。脂肪组织是雌激素合成的场所。跟肥胖有关的胰岛素和胰岛素样生长因子的水平升高，造成oestradiol（雌二醇）的增加，可能提高女性的testosterone（一种雄性激素）水平（极度肥胖会造成多囊卵巢疾病）。性激素水平升高与子宫内膜癌和乳腺癌（更年期后）有密切的关系（不过，肥胖如果是更年期前，也可能有预防乳腺癌（更年期前）的作用，原因是会有无卵月经期，降低了雌激素水平）。
3）肥胖影响人体发炎系统。
肥胖伴随一种慢性发炎状态。脂肪细胞产生促发炎的因子。胖人的循环肿瘤坏死因子TNF-a，白细胞介素IL-6，
C-reactive蛋白，以及瘦素都是发炎的细胞因子。这样的慢性发炎状态是促癌发生的。
所以，肥胖者与健康者之间，有上述一些重要的差别，并不是仅仅多长一点肥油肥肉那么简单。这个报告认为，改变肥胖要从怀孕期的孕妇饮食控制开始，婴儿出生后的哺乳，以后成长期的身体肥胖度控制，都要考虑预防癌症这个目标。报告还指出，甚至身体过高，也比正常人有较高的癌症风险。如此看来，防止肥胖和体重过重，不是一个简单的多几斤肥肉的问题；减肥不是为了好看，而是降低癌症风险。这一点我们大概还认识不到吧？
人类总会逐步找到更好的预防方法。2008夏天世界癌症基金会要再发表一个资料。我的后续帖子也有一些建议。大家应采取积极态度，尤其是病人家属。因为家庭痛苦造成严重的“自由基负担”。家人免疫力下降，导致不少家属后来患病。这是夫妻癌现象的解释之一。
保健和预防，应从年轻一代做起。现在国内大病年轻化是一个严重问题。我个人认为学校应该设立比较深入的疾病知识课程。全国到处都是医盲，社会成本太高，家庭痛苦也太多，本该做早期预防的。现在连牙齿保健都没有做，与西方差距太大，病夫如何崛起于世界？靠几个金牌运动员吗？
每虑及此，痛感官僚无能、教育者愚昧，老百姓无奈。我只有埋头做这样本来不是自己的事情，多一份宣传，多一人受惠，少一份悲哀。我只是慵散论坛的一个路人而已，不认识任何版主什么的，看见癌症病人的悲剧，心有不恻，象着魔似的不断写帖子，我甚至不理解自己何以这样。有人问我为什么，我只有苦笑。在这样的时代，剩下的不就只有一点点人性同情还有价值吗？各位读者，多多保重。我也许那天就告辞了。
==== 汉译英 ====
This quote explain the first proposal. Perhaps the readers are familiar with the body fat, overweight, obesity will lead to cardiovascular disease. However, the relationship of obesity with cancer do? I am afraid that most people will shake their heads.
Degree of body fat, the relationship between overweight and cancer
World Cancer Fund in 2007 an expert report on the recommendations of a cancer prevention is to minimize the level of body weight to standard weight, not overweight, obesity, and start from childhood. Through the examination on the experimental report literature, the report lists six kinds of cancer, that obesity and overweight with body-related, and that this relationship between the two is convincing (sure of). Obesity includes two, one overall obesity, and six kinds of cancer, they are
1) esophageal cancer
2) endometrial cancer
3) pancreatic cancer
4), colon cancer
5) breast cancer (after menopause)
6) kidney cancer
The other is abdominal obesity, and colon cancer.
You may feel a bit incredible, obesity seems to be less harmful, right?
In certain extent, this report uses three evaluations, the first stage is convincing (sure of); second level is probable (very likely); The third level is limited suggestive (limited prompt). Due to space limitations, we have focused on within the first tier assessment. The above-mentioned six kinds of cancer with obesity related to evaluation findings have been convinced that class. Argument on the evaluation methods, such as how to use Forest Plot map, how to analyze the statistical credibility, how to conduct the meeting deliberations, the limited space here to talk about can only be omitted. Readers who are interested can read the original text itself.

Should be the need to explain the logic behind this statement. The report draws primarily on two documents, one in 2003 Hursting and others paper "caloric restriction, aging, cancer prevention (Calorie, Aging, and Cancer Prevention)" and 2004, Calle EE et al's paper "overweight, obesity disease and cancer (Overweight, Obesity and Cancer) ", the promoter for the mechanism behind obesity, with the following explanation.

1) Obesity is harmful to human insulin-like factor IGF-1, insulin and leptin.
Their levels of obesity increase the body can promote the growth of cancer cells. In particular, abdominal obesity, insulin resistance caused by
Canada, so that the role of the pancreas compensate for increased insulin production. Resulted in an increase of the colon and endometrial cancer risk. Also may increase the risk of kidney cancer. The cycle of obese leptin (Leptin) high, with the colon and prostate cancer.

2) Obesity is affecting steroid hormones.
Estrogen, androgen, progesterone is likely to play a role in obesity and cancer. Adipose tissue is a place of estrogen synthesis. With obesity-related insulin and insulin-like growth factor levels rise, resulting in oestradiol (estradiol) increases, may increase women's testosterone (a male hormone) level (extreme obesity can cause polycystic ovarian disease). Elevated levels of sex hormones and endometrial cancer and breast cancer (after menopause) are closely related (however, if it is pre-menopausal obesity may also be the prevention of breast cancer (pre-menopausal) role, because there will be no egg menstrual period and lower estrogen levels).
3) inflammation of obesity affect the human body system.
Obesity associated with a chronic inflammatory state. Fat cells to produce pro-inflammatory factor. Fat people circulating tumor necrosis factor TNF-a, interleukin IL-6,
C-reactive protein, and leptin are the inflammatory cytokines. This state of chronic inflammation of the promoter to happen.
So, between obesity and health, there are some important differences between the above-mentioned is not just a little longer Feiyou more fat so simple. The report that the change of fat from the diet of pregnant women during pregnancy begin breast-feeding after birth, after the growth period of the body fat degree of control and prevention of cancer must take into account this goal. The report also pointed out that even the body is too high, have a higher than normal risk of cancer. In view of this, to prevent obesity and overweight is not a simple issue of fat more than a few catties; weight loss is not to look good, but to reduce risk of cancer. This is something we probably still do not recognize it?
That mankind will always find a better way to prevent the progressive. 2008 Summer Cancer Foundation would like to make a world of information. I have some suggestions for follow-up post. We should adopt a positive attitude, especially the patient's family. Because of family suffering severely, "the burden of free radicals." Family, decreased immunity, leading to a lot of family members was sick. This is one of the interpretation of the phenomenon of husband and wife cancer.
Health care and prevention, should start with the younger generation. China is now seriously ill young is a serious problem. Personally, I think schools should set up a more in-depth knowledge of the disease course. National Medical everywhere blind, the social cost is too high, families are suffering too much to do this early prevention. Now, even dental care has not done so, the gap with the West too, the sick man how to rise in the world? Number of gold medals by athletes?
Each taking into account of this, the pain bureaucratic incompetence, educators, stupid, helpless people. I can only do this kind is actually not hard at their own thing, more of a propaganda, one more people would benefit and less sad. I was just careless casual forum for a passer-only, do not know what any moderator, he saw the tragedy of cancer patients, the heart has not sorrowful, like the obsession continued to write similar posts, I do not even understand their own so why. Some people ask me why, I can only smile. In such times, the rest of humanity is not only a little sympathy there value? You readers, take care. I may be the day on the left.