Type 2 diabetes can cause a number of health complications that decrease the life expectancy of patients. Apart from causing heart disease, stroke, nerve damage, kidney disease and eye problems, research also shows that there is a connection between type 2 diabetes and cancer.
For more than 50 years, physicians have been reporting cases of cancer occurring in patients with type 2 diabetes. However, the data had been inconclusive when it comes to pointing to a connection between the two conditions. In the 1960s, large population studies finally found that risks of cancer increased for people with type 2 diabetes. While relative risks imparted by diabetes for cancers of the liver and pancreas were twofold or more, the relative risks of colorectal, breast and bladder cancers were slightly lesser (1.2 to 1.5 fold.)
4 Factors That Increase The Risk of Cancer with Type 2 Diabetes
While insulin is vital for glucose metabolism, more of it can be harmful to the body. Hyperinsulinemia (either due to excessive production of insulin by the body or due to injected insulin) is the root cause of increased risk of cancer among diabetics.
For insulin to function as a messenger, it needs to bind to specific receptors on target cells. These receptors are present on a variety of cells. Large amounts of insulin will activate a far greater number of receptors than it should normally do. This excessive binding can create a chain of events that may lead to the cell becoming cancerous.
Reduced Production of IGF-Binding Protein
There is another theory that explains why hyperinsulinemia causes cancer. There is a protein in the body called Insulin-like Growth Factor or IGF. Being a growth factor, it affects the growth rates and patterns of cells. To keep this potent protein in check, the liver produces a protein called IGF-binding protein. Large amounts of insulin reduce the production of IGF-binding protein in the liver. This results in large amounts of circulating IGF that can bind to cells and make them cancerous. Insulin receptors are expressed by cells of the colon and rectum, breast, pancreas, and liver. And this explains the increased risk of cancer of these organs as a result of hyperinsulinemia.
Along with elevated levels of insulin, the inflammatory nature of type 2 diabetes also increases the risk of cancer. Chronic inflammation caused by impaired glucose metabolism can also make normal cells cancerous. A chronic state of hyperglycemia facilitates cancer progression. Cancer cells show very high rates of glucose uptake and metabolism. This is the basis of the FDG-PET imaging of cancers, where cancer cells and the progression of cancer is identified by imaging cells showing a high uptake of glucose molecules.
Obesity, which is seen in a majority of type 2 diabetics, can also contribute to cancer risk. Fat tissue is an active hormone-producing (endocrine) organ. Excessive fat tissue will obviously produce large amounts of hormones, most of which are growth and inflammation promoters. High levels of circulating growth hormones can increase the risk of normal cells becoming cancerous. Inflammatory hormones will create a state of chronic, low-grade inflammation in the body that may eventually lead to cancer.
Type 2 Diabetes And Cancer: Final Thoughts
While cancer alone is difficult to treat, it becomes an even bigger challenge to try to treat cancer with type 2 diabetes. This is because many anti-diabetic medications interfere with conventional cancer treatment. Similarly, conventional chemotherapy also interferes with glucose metabolism that may lead to hyperglycemia.
We need a greater understanding of the events that link type 2 diabetes and cancer. An improved understanding of these mechanisms can help in the development of therapy for individuals with diabetes who have developed cancer.
At Sepalika, we believe that type 2 diabetes is reversible. This reversal is easier at the earlier stages (prediabetic stage). Catching the condition in the earlier stages is important for the success of reversal. This can happen only with continuous monitoring of blood glucose levels if you are at a risk of type 2 diabetes. A combination of diet and lifestyle changes can help you reverse diabetes and reduce the risk of health complications, such as cancer, that can come with it.