糖尿病女性患大肠癌风险大
From 自明知识
糖尿病妇女已经有很多需要处理的复杂的诊断和治疗的指南。而现在另一个令人闻风丧胆的诊断：大肠癌可能也要加入其中。
根据在周五公布的研究结果，糖尿病妇女罹患大肠癌（即在结肠或直肠组织癌组织的生长）的可能性要比那些没有代谢综合症的患者高1.5倍。这个研究结果在周五召开的美国肿瘤协会的第六届世界癌症研究会议的肿瘤预防前沿会议上公布交流。
“我们刚刚开始了解胰岛素在增加其他肿瘤发生率中的作用。”，Andrew Flood博士说。Andrew Flood博士是这个研究的主持者，也是明尼苏达州大学公共卫生部的流行病学与社会保健专业的副教授。“在这个研究中，最初我们发现：诊断为糖尿病的妇女，意味着发生结肠直肠癌的机会高50％。”Flood博士和他的同事们研究了来自于大规模的肿瘤筛查研究－乳腺癌示例研究计划（the Breast Cancer Demonstration Project）的数据。这个研究在70年代进行，有29个不同的医疗机构参与了这项研究。他们追踪了至少45000名参与的妇女，以确定后来有多少妇女发生了结肠直肠癌。在调整了那些可变因素后，Flood博士说，结果依然有显著的统计学差异，而且他相信胰岛素在这其中起了一些作用。“胰岛素水平的升高本身也许就增加了危险性。”他说。
高胰岛素水平意味着高危险性？
David Beck博士，是纽奥尔良市的Ochsner临床基金会的结肠和直肠外科的主席，他也认为胰岛素可能在肿瘤的进展中扮演了重要的角色。
“胰岛素对于细胞应用糖的能力而言是非常重要的。糖被认为是细胞很大的能量的来源。”，他说，“血糖水平的升高可能可以一开始支持细胞的生长或者与新生血管的生长有关，这些都能加速细胞的生长。这也许是其他肿瘤生长的一个因素。”
为了验证胰岛素升高是癌性息肉的促发因素（胰岛素水平的升高在那些发展中的糖尿病患者以及那些血糖控制不佳的糖尿病患者中十分的常见），Flood博士和他的同事们研究了从那些后来诊断为糖尿病患者的妇女身上得来的数据。他们惊奇的发现，在那些所谓的“糖尿病前期”的妇女身上，没有发现大肠癌患病的危险性增加的现象。
“糖尿病前期的患者经常有胰岛素水平的升高，所以我们想也许在糖尿病前期的患者存在类似的高危因素。”，Flood博士说，“但是我们并没有这样的发现。”胰岛素加速肿瘤细胞生长的确切原因，目前并不明确。Flood博士猜测可能与胰岛素在体内的时间的延长以及胰岛素水平的增高有关。Flood博士说，需要进一步的研究确定糖尿病妇女和发生结肠直肠癌的统计学的关系，并且明确是否有发生其他肿瘤的可能。他指出胰腺癌可能是其他能被胰岛素影响的疾病。“对于糖尿病的妇女而言，能帮助她们不得结肠癌最好的方法是控制她们的血糖。”Flood博士补充说，“这也是她们实实在在应该做的”。
BECK博士提醒患者们，息肉的结肠镜检查是防御结肠直肠癌的第一道防线。“健康的生活方式和饮食是十分重要的，但是对于预防大肠癌而言，肠镜是结肠直肠癌的筛查是关键。” 他说，“如果糖尿病妇女患大肠癌的危险性是增加的话，那么对她们进行筛查更重要，而且我们也许应该考虑缩短她们的随访周期“
Diabetes Increases Colorectal Cancer Risk for Women
Women with diabetes already have to manage a complex diagnosis and treatment protocol. Now they may have another disconcerting diagnosis: colorectal cancer.
According to a study released Friday, women with diabetes are 1.5 times more likely to develop colorectal cancer -- in which cancerous tumors develop in the tissues of the colon or rectum -- than women who don't have the metabolic disorder.
The research was announced Friday at the American Association for Cancer Research's Sixth Annual International Conference on Frontiers in Cancer Prevention Research.
"We are just beginning to understand the role of insulin in the increased risk of many cancers," said Dr. Andrew Flood, the study's lead author and assistant professor of epidemiology and community health at the University of Minnesota School of Public Health.
"Our primary finding in this study was that a diagnosis of diabetes meant a 50 percent stronger chance of developing colorectal cancer."
Flood and his colleagues examined data from a large-scale cancer screening study known as the Breast Cancer Demonstration Project, which took place during the 1970s at 29 different medical facilities. They tracked the records of more than 45,000 female participants to identify how many women later developed colorectal cancer.
After adjusting for a number of variables, Flood said the results remained statistically significant, and he believes insulin has something to do with it.
"Elevated rates of insulin itself may promote the risk," he said.
Higher Insulin Means Higher Risk?
Dr. David Beck, chairman of the department of colon and rectal surgery at the Ochsner Clinic Foundation in New Orleans, agrees that insulin may play a role in cancer development.
"Insulin is important in cells' ability to use glucose, one of the cells' major energy source," he said. "Elevated glucose levels might support cell growth initially or may contribute to new blood vessel growth, which would allow cells to grow faster. This might be a factor in other cancer development."
To test the hypothesis that higher insulin levels -- common in people developing diabetes or people who have poorly managed glucose -- triggered cancerous polyps, Flood and his colleagues then examined other data from women who were later diagnosed with diabetes. They were surprised to find that women in this "prediabetic" stage did not actually have as high an increased risk.
"People who are prediabetic have higher levels of insulin, so we expected to see a greater risk," said Flood. "But that's not what we found."
The exact way reason that increased insulin hastens the development of cancer cells remains largely unknown. Flood suspects it may have something to do with the length of time and the degree of elevated insulin in the body.
Flood said that further study needs to be done to find statistics for diabetic men and development of colorectal cancer and to determine the the risk of developing other cancers. He points to pancreatic cancer as another possible illness that insulin can affect.
The best way women with diabetes can help their bodies not to develop colorectal cancer is through "management of glucose," according to Flood. "That's what they can do."
Beck reminds patients that colonoscopies that look for polyps are the first line of defense.
"Healthy lifestyles and diet are important, however colorectal cancer screening with colonoscopy is critical to the prevention of colorectal cancer," he said. "If diabetic women are at increased risk, it is even more important to screen them and we may consider decreasing the time for follow-up exams."