But, most people are not aware of the connection between diabetes and cancer. At least 31% of diabetics may develop some form of cancer, again if they have poor blood glucose control and other comorbidities such as chronic inflammation and obesity.
According to a report in the Journal of the American Medical Association, cancer patients who already have diabetes have a greater chance of dying of the disease than cancer patients who do not have diabetes.
According to a 2010 consensus report published jointly by the American Diabetes Association (ADA) and the American Cancer Society (ACS), the risk of a person with type 2 diabetes developing cancer is 20-50 percent higher than a person without diabetes. Research also indicates that people with type 2 diabetes who develop cancer may experience a shorter life expectancy. Being overweight increases the odds of cancer reoccurrence.
About 30 million people in the United States have diabetes, and about eight to 18 percent of newly diagnosed cancer patients also have the disease. Ref: Health.com: Top 10 diabetes stories of 2008.
Compared with Caucasian Americans, the risk of diagnosed diabetes is 77 percent higher among African Americans, 66 percent higher among Hispanics Americans, and 18 percent higher among Asian Americans.
Researchers found that people with diabetes had about a 1.4 times greater risk of dying of cancer than patients without diabetes. Mortality seemed to be higher for many types of cancer, but it was only statistically significant for three types: breast, endometrial, and colorectal. Ref: Health.com: What's your breast cancer IQ?
Obesity and type 2 diabetes increase the risk for endometrial (uterine) cancer by 39 percent, esophageal cancer by 37 percent, kidney cancer by 25 percent, colon cancer by 11 percent and post-menopausal cancer by 9 percent.
People with diabetes experience a higher prevalence of the following cancers:
Breast cancer in women (postmenopausal)
Endometrial (the lining of the uterus in women)
Pancreatic (thought to be a risk factor for diabetes)
Biological and Lifestyle Factors
There are many reasons why people with diabetes might have a higher cancer-mortality risk. Here is a list of the major reasons:
Blood Sugar: High blood sugar in diabetics makes a person more prone to having damaged DNA. In addition, high blood sugar fuels cancer cells and enable tumors to grow faster.
Insulin: High insulin levels stimulate cell growth and insulin growth factors. This stimulates the growth of cancer cells, which in turn stimulate the formation of new blood vessels. The vessels then provide nourishment to cancerous tumors.
Immunity: People with diabetes are more susceptible to infections and have a weaker immune system, which makes them susceptible to certain cancers.
Risk Factors: Some of the risk factors associated with diabetes are common to cancer, e.g. poor diet, sedentary lifestyle, obesity, vitamin deficiency (especially Vitamin D).
Obesity: Overweight people have higher levels of inflammation markers. Inflammation fuels cancer. Also, overweight people have lower levels of adiponectin, a hormone secreted by adipose tissue (fat), which may accelerate cancer growth. Adipose tissue is like an endocrine gland, putting out a number of hormone-like substances, which may play a role in turning normal cells into cancerous ones, or promote cancer cell growth.
Pancreas: In diabetics, the pancreas is over-stressed and inflamed while producing excess amounts of insulin to keep up with the glucoise demands. This weakens the pancreas and makes it more susceptible to becoming cancerous.
Note: In some cases, a sudden change in blood sugar levels in diabetics who previously had well-controlled diabetes may be a sign of pancreatic cancer. Therefore, see your physician as soon as possible for a checkup to ensure this is not the case.
Artificial Sweeteners: Many diabetics were duped into using Splenda® in place of sugar. But, Splenda® contains chlorine which is carcinogenic, this may cause cancer! Refer to the Cancer & Nutrition post for more details.
Diabetic Medications: Recent studies now indicate that some diabetic drugs may trigger cancer in some people. Even the FDA is concerned about this. About 50% of Type 2 diabetics and all Type 1 diabetics take insulin daily, and insulin is known to stimulate cell growth.
Mental State: One other possible factor is depression. About 10 to 40 percent of people with diabetes also experience depression because of low serotonin and high cortisol levels. Studies have shown that depression can weaken the immune response.
Insomnia: Lack of quality REM sleep prevents the body from going into repair mode in diabetics and overweight people. This causes the body to delay or not produce the hormone melatonin, which is known to have anti-cancer benefits.
Reports and References
Here are some documented reports and references concerning the link between diabetes and cancer.
Breast Cancer Advances More Quickly in Diabetes: Diabetes Forecast
Breast cancer appears to advance more quickly in women with diabetes, a study found. When researchers compared records of women ages 20 to 105 diagnosed with breast cancer, including about 6,000 with diabetes and more than 32,000 without, they found that those with diabetes had larger tumors, a 14 to 21 percent greater risk for a more dangerous stage of tumor, and a 16 percent greater chance of the cancer having spread to the lymph nodes.
Diabetes increases late-life risk of thyroid cancer
Researchers found that the presence of diabetes increased the 10-year risk of thyroid cancer by one-quarter among adults 50 to 71 years old. The team based its conclusions on data collected from the nearly 500,000 men and women who participated in the NIH-American Association of Retired Persons (AARP) Diet and Health Study, which was conducted in 1995 and 1996.
Published in the journal Thyroid, the investigation was conducted by epidemiologists associated with the National Cancer Institute (NCI) and the National Institutes of Health (NIH).
Probability of pancreatic cancer following diabetes: a population-based study.
Approximately 1% of diabetes subjects aged > or =50 years will be diagnosed with pancreatic cancer within 3 years of first meeting criteria for diabetes. The usefulness of new-onset diabetes as marker of early pancreatic cancer needs further evaluation.
Diabetics twice as likely to develop cancer, suggests new study - NaturalNews.com
A new study published in the journal Diabetes Care reveals that diabetics have a nearly doubled risk of developing certain types of cancer compared to those without the disease. Dr. Chaoyang Li from the US Centers for Disease Control and Prevention (CDC) in Atlanta, Ga., and his colleagues found that 16 percent of diabetic men and 17 percent of diabetic women develop cancer, while only seven and ten percent of the general population, respectively, develop it.
The report explains that the most dramatic increase is seen in those with pancreatic cancer, as diabetic men appear to be 400 percent more likely to develop the cancer than others. And in women, those with diabetes tended to be up to three times more likely to develop blood cancer than women without the disease.
Research Dr. Brancati published in 2008 revealed that the death rate from cancer is about 40 percent higher in diabetics than it is in the general population as well, illustrating once again a clear connection between diabetes and compounded cancer risk.
Type 2 Diabetes Linked to Cancer Deaths
A recent meta-analysis conducted by Dutch researchers shows that people with type 2 diabetes are not only more likely to develop these cancers, they are more likely to die from them as well. Their findings were presented at the 2013 European Cancer Congress.
The meta-analysis, which is a study that evaluates results from several independent studies, analyzed the results of 20 studies involving over 1.9 million people between 2007 and 2012. The findings showed that people with type 2 diabetes had a 23 percent increased risk of developing breast cancer and a 38 percent increased risk of breast cancer mortality. In addition, type 2 diabetics displayed a 26 percent increased risk of developing colon cancer and a 30 percent increased risk of dying from it.
Study: Diabetes Patients Are More Likely to Develop Lung Cancer
Researchers at Mary Babb Randolph Cancer Center at West Virginia University report that women with type 2 diabetes were 27 percent more likely to be diagnosed with lung cancer compared with the general population. Women in the study who treated their diabetes with insulin had a 71 percent increased risk for lung cancer.
The study was published in Diabetes Care and tracked 145,765 postmenopausal women ages 50 to 79. Information about diabetes treatment was self-reported. J. Luo and his colleagues concluded that the increased risk did not apply to women with untreated diabetes or the length of time a patient had suffered from the disease.
Earlier this year, another study associated the use of insulin and glinide drugs in type 2 diabetes patients with an increased risk of several types of cancer. C. H. Chang and his team at the Institute of Preventive Medicine at National Taiwan University linked the medicines to higher risks for liver cancer, colorectal cancer, lung cancer, stomach cancer and pancreas cancer.
A third study in 2012 found possible correlations between type 2 diabetes and an increased risk of cancer and also insulin use and higher rates of cancer. Researchers at Steno Diabetes Center in Gentofte, Denmark, analyzed data from the Danish National diabetes Register and Cancer Registry and concluded that diabetes patients who did not use insulin had a 100 percent increased risk of developing cancer at the time of their diagnosis. That risk dropped to 15 percent after two years.
B. Carstensen B and his colleagues also found that type 2 diabetes patients being treated with insulin had a 400 percent increased risk of developing cancer at the beginning of treatment. The risk dropped to 30 percent after five years of insulin therapy.
Diabetes and Bladder Cancer Risk
Type 2 diabetes patients already have a higher risk of bladder cancer — perhaps as much as a 40 percent increase over the general population, studies have shown. And diabetes patients who take the widely prescribed drug Actos may boost that risk by another 22 percent, for a total of a 62 percent increased risk, according to a study published July 3, 2012, in the Canadian Medical Association Journal.
The U.S. Food and Drug Administration also has warned that the use of Actos for more than one year could be linked to a higher risk of bladder cancer. The agency based its June 2011 safety alert on the five-year interim results of a 10-year study being conducted by Actos manufacturer Takeda Pharmaceuticals. Final results of that study are expected next year.
Sugar the Reason Diabetics Have a Higher Risk of Aggressive Cancers
Cancer Cells Bypass Insulin Roadblocks
The report, published last week in the journal Cell, outlines Cagan's findings. Most importantly, it shows that even though a cancer cell's insulin pathways don't work in diabetics, cancerous tumors get around that roadblock and trigger the insulin receptors regardless. As a result, cancerous tumors metastasize and spread to other parts of the body.
Cagan, a professor of developmental and regenerative biology, explained that Ras and Src, “classic human cancer genes,” can act similarly in fruit flies. When dietary sugar combines with these genes, it activates a pathway that allows the cells to take in sugar. “Tumors love sugar,” Cagan said. “It helps them grow.”
The diabetes-cancer link is most often found in people with cancers of the pancreas, breast, liver, or colon, Cagan said.
Why Does Diabetes Raise Cancer Risk?
Diabetes doubles the risk of liver, pancreas, and endometrial cancer. It increases the risk of colorectal, breast, and bladder cancer by 20% to 50%.
People with diabetes tend to have some known risk factors for cancer: older age, obesity, poor diet, and physical inactivity. And problems common in diabetes -- too-high insulin levels, too-high blood sugar levels, and inflammation -- increase cancer risk.
Do Diabetes Treatments Raise Cancer Risk?
There is evidence, but not definitive proof, that diabetes treatments affect cancer risk.
Metformin, the most commonly used diabetes drug, seems to lower cancer risk. But there's also evidence from some studies -- contradicted by others -- that insulin, particularly long-acting insulin glargine (Lantus), may increase cancer risk.
Moreover, there are at least theoretical concerns that other relatively new diabetes drugs may affect cancer risk.
More About the Cancer-Diabetes Link
The following are just a few of the many articles and reports about the link between diabetes and cancer.
FDA Investigates Cancer Link to Popular Diabetes Drugs - Dr. Mercola
Diabetes and Cancer Consensus Report
Diabetes Increases Cancer Risk by 20 Percent
Prediabetes Linked to Higher Risk of Cancer, Study Finds
Pre-diabetes Can Increase Risk Of Developing Certain Types Of Cancer By 15%
Linking Diabetes to Cancer: Changes for Prevention | American Institute for Cancer Research (AICR)
|Pancreatic Cancer | Everyday Health|
|The Diabetes and Cancer Connection | Diabetic Living Online|
Diabetes and Colon Cancer: An Emerging Link
The Cancer, Diabetes, and Heart Disease Link
|Lack of sleep increases risk of cancer, heart disease and diabetes | Daily Mail Online|
|People with diabetes more likely to get cancer - Reuters|
Type 2 Diabetes Might Raise Risk of Liver Cancer
The Diabetes–Cancer Link: Coming to a Consensus
Diabetes and Cancer: American Diabetes Association
Diabetes and cancer: A shared biological basis -- ScienceDaily
Mysterious Link Connects Diabetes And Cancer : Shots - Health News : NPR
Many Diabetes Drugs Under FDA Review, Linked to Cancer
Januvia & Janumet – Pancreatic Cancer & Other Side Effects
Diabetes drugs linked to cancer of the pancreas and other health problems | Daily Mail Online
Diabetes drugs linked to pancreatic cancer risk
Do Diabetes Drugs Cause Cancer? - The People's Pharmacy
Diabetes Tied to Higher Risk of Pancreatic Cancer in Study