The Diabetes and Cancer Link

Researchers have found several connections between diabetes and cancer.

 

Although that may come as frightening news, some of the evidence may come as a surprise: some types of cancer rates are higher while rates of other types are lower in people with diabetes, a common medicine for type 2 may prevent cancer, and a cancer drug may help prevent type 1 diabetes.

 

Research Findings

A recent large-scale study following over 125,000 people with type 2 diabetes lead by Dr. Kari Hemminki of the German Cancer Research Center, found an increased risk for 24 types of cancer. The most significant rates were for pancreatic and liver cell cancers (elevated by factor 6 and more than 4 times the risk respectively compared to the general population). Since pancreatic cancer and diabetes both involve the pancreas, evidence remains unclear on whether diabetes causes or results from the cancer. Risk for cancers of the kidneys, thyroid, esophagus, small intestine, and nervous system were more than twice the rates of those without diabetes.

 

Other studies have found the following:

1.    Meta-analyses from 15 studies and 2.5 million people with diabetes resulted in a 30 percent more likelihood of developing colorectal cancer. Women with type 2 over the age of 55 had double the risk.

 

2.    Women with diabetes had a 20 percent greater risk of developing breast cancer. People with breast cancer treated with chemotherapy and metformin have better outcomes.

 

3.    Metformin use is associated with an anti-cancer effect as those who take it have substantially lower cancer rates (62 percent lower risk of pancreatic cancer and up to 37 percent reduced risk for all cancers). Notably, research has also shown that people with diabetes already diagnosed with cancer may respond better to chemotherapy when treated simultaneously with metformin.

 

4.    Those who take both Actos or Avandia and metformin have a 35 percent reduction in cancer mortality.

 

5.    Further research is needed to better understand the risks and mechanisms that appear to link insulin with tumor growth. This finding may have more to do with insulin resistance rather than a direct effect of insulin itself.

 

6.    Men with type 2 diabetes have a significantly lower rate of prostate cancer (may be related to lower levels of testosterone).

 

7.    The combined effect of smoking, excessive drinking, poor diet, and physical inactivity significantly raises premature death from all causes, including cardiovascular disease and cancer. Cumulative survival, adjusted for subject age at baseline and sex, was 96 percent for those who had none of the poor health behaviors measured, compared with 85 percent for those who had all four poor health behaviors.

 

8.    Rituxamab, a drug that treats lymphoma and rheumatoid arthritis, may soon be used to help stop the destruction of pancreatic beta cells in newly diagnosed cases of type 1 diabetes. A one-time dose of Rituxamab temporarily slows or stops the destruction of the 10 or 20 percent of beta cells that type 1s typically have remaining when they are first diagnosed. Further studies are needed to assess the impact of ongoing treatments.

 

9.    Childhood cancer survivors have double the risk of getting diabetes based on the type of treatment received (anticancer radiation therapy may damage the pancreas). Ongoing endocrine follow-up is important for these children.

 

Dr. Ulf Smith summarized these findings in a sobering statement, "One point has become abundantly clear … cancer must now be numbered amongst the complications of diabetes."

 

What You Can Do

Take this in stride. Keep in mind that self-care behaviors such as healthy eating, being active, and controlling weight either decrease or increase the risk for cancer and diabetes depending how consistent you are with them.

 

Until we have national guidelines on how best to incorporate this research into our standards of practice, advocate for yourself. Ask your provider about getting screened for cancer, get regular mammograms, colonoscopies, prostate exams, and the like.

 

Conclusion

Evidence remains unclear as to why people with diabetes have higher rates of cancer. As research continues to unfold, it is important to stay informed in order to maintain awareness, minimize risk with healthy living, discuss screening tests with your provider, and get help early on if something doesn't feel right in your body. Ongoing efforts to maintain glucose control remain paramount.

 

 

NOTE: The information is not intended to be a replacement or substitute for consultation with a qualified medical professional or for professional medical advice related to diabetes or another medical condition. Please contact your physician or medical professional with any questions and concerns about your medical condition.