DM and CA: Is There a Link between Diabetes and Cancer?
Have you ever noticed that whenever you read a list of risk factors for a disease, diabetes is almost always there? Heart disease, Osteoporosis, Kidney disease, and cancer to name just a few. The link between diabetes and other diseases is sometimes causative.
For example, elevated blood sugars have a direct impact in increasing our risk for kidney disease. However, far more often we have a correlative link. This is when we see increased incidence of a disease in people with diabetes, but we have not identified the cause of that increase.
This is also true of diabetes and cancer risk. We see a roughly 10% higher cancer risk in people with diabetes compared to those who do not have diabetes, but have similar other risk factors (age, BMI, smoking, etc) a recent analysis study has shown a particular increase in the occurrence of liver, pancreatic, breast, ovarian, endometrial and gastrointestinal cancers in people with diabetes. This study also shows an increase in cancer risk for people with type 2 diabetes over type 1 diabetes, largely because advanced age is a major risk factor for both cancer and type 2 diabetes.
Though we can not identify the cause of this increased risk (hyperglycemia, chronic hypoglycemia, hyperinsulinemia, hormonal dysregulation, chronic inflammation, and other causes have all been posed as possible causal factors) we have a correlation that should raise awareness of cancer screening and risk reduction for people with diabetes.
There are medications that are sometimes used to treat diabetes that have been associated with increased cancer risk in some individuals. TZDs such as pioglitazone (Actos) and rosiglitaszone(Avandia) for example have carried a warning risk of thyroid cancer, however data has disproved this as a causative impact.
Discussing these risk factors, in combination with family history and other cancer risk factors to determine a medication regimen that will minimize cancer risk is important. However, there are also studies that have shown Metformin to reduce cancer risk in people with diabetes. There is still a great deal of study in this area and data is not conclusive as to causative impact of diabetes medications and cancer.
What can people with diabetes do to minimize cancer risk?
Stop Tobacco use NOW: Tobacco use in all forms has been shown to greatly increase risk for nearly every form of cancer. It is never too late to quit smoking and reduce your risk. Even someone who has smoked for decades reduces their cancer risk the day they quit! After 10 years cancer risks from smoking are cut in half! And after 15 years smoke free cancer risks return to that of someone who never smoked at all!
Maintain good blood sugar management: stable blood sugar management has been shown to reduce inflammation and other complications (such as nephropathy, and CVD) that can also increase cancer risks.
Discuss medication pros and cons with your healthcare team: If you have an elevated cancer risk discussing your medications (For diabetes and other diagnoses) with your providers is an important piece to minimizing cancer risk
Discuss use of off-label medications to reduce insulin needs: hyperinsulinemia, or a state in which we have an excess of insulin in our bodies, has been linked to hormonal dysregulation, particularly reproductive hormone dysregulation in women. This dysregulation has been linked to increased cancer rates in women. Adding an off label medication for the treatment of type 1 diabetes can reduce insulin needs and reduce this dysregulation. Metformin, SGLT2s and GLP1 medications have all been used to reduce insulin needs in people with type 1 diabetes.
Exercise: Regular physical activity reduces insulin needs, reduces long term complication risks, and has been shown to reduce cancer risks in people with and without diabetes.
Get screenings: People with diabetes should consult with their physicians to determine a schedule for appropriate cancer screenings. Key among these are breast and reproductive exams for both men and women(including post menopausal women) , skin cancer exams (Skin cancer has been shown to increase risk for other cancers), colon cancer screening. Routine medical exams with primary care providers, annual retinal screenings and routine endocrine screenings have also been shown to improve detection rates of various forms of cancer.
One alarming statistic this study found was that, when diagnosed with cancer, people with diabetes typically receive less aggressive treatment, which can increase mortality rates. This also illustrates the importance of good blood sugar management. Poor blood sugar management can slow healing which can be a major limiting factor in how aggressively cancer can be treated. Timing is key in cancer treatment regimens, so working closely with your diabetes team to maintain blood sugar management before, through, and after treatment leads to far better treatment outcomes.
I have had the privilege of working with patients through cancer treatment and it is certainly possible to maintain good blood sugar management, but it is a complicated process with a lot of dynamic pieces to keep in mind. As an RN and CDCES I use my skill sets to help patients through all aspects of treatment.
More information from the study sited above can be found at: http://www.diabetesincontrol.com/the-relationship-between-diabetes-and-cancer/