Diabetes Medications May Impact Cancer Risks

Type 2 diabetes medications lowered the risk of cancer in women

(RxWiki News) People with type 2 diabetes have higher cancer risks than the general population. The link may have to do with how diabetes affects the metabolism. Diabetes medications may also figure into the equation.

Specific diabetes medications were shown in a new study to significantly lower the cancer risks of women with type 2 diabetes.

Other types of medications used to treat diabetes were linked to higher cancer risks in women.

Anti-diabetic agents didn’t affect cancer risks of men, the study found.

"Talk to your doctor about the risks associated with the medications you’re prescribed."

Investigators led by Sangeeta Kashyap, MD, an endocrinologist and associate professor of medicine at Cleveland Clinic's Endocrinology & Metabolism Institute, compared two types of medications used to treat type 2 diabetes — insulin sensitizers and insulin secretagogues.

Insulin sensitizers lower blood sugar and insulin levels in the body by increasing the muscle, fat and liver's response to insulin. Insulin secretagogues lower blood sugar by stimulating pancreatic beta cells to make more insulin.

Insulin sensitizers include the following:

  • Biguanides include metformin, which is sold under a variety of brand names including Glucophage and Fortamet, and Riomet.
  • Thiazolidinediones include rosiglitazone (brand name Avandia) and pioglitazone (brand name Actos).

Insulin secretagogues include:

For this study, Dr. Kashyap and team reviewed and compared information on 25,613 patients in the Cleveland Clinic Diabetes Registry with the tumor registry of 48,051 cancers diagnosed between 1998 and 2006.

During follow-up, 892 patients with diabetes were diagnosed with cancer.

Women with type 2 diabetes taking insulin sensitizers — including metformin, Avandia and Actos  — had a 21 percent decreased cancer risk compared to women taking insulin secretagogues.

Female diabetes patients taking thiazolidinediones (Avandia and Actos) had a 32 percent reduced cancer risk compared to women taking sulfonylurea (DiaBeta, Micronase, Glucotrol, Glynase, Amaryl).

"What this study shows us is that using insulin secretagogues to increase insulin production correlates with an increased cancer risk in women with type 2 diabetes," Dr. Kashyap said in a statement. "By contrast, insulin sensitizers cut insulin levels and can decrease cancer growth. So, clearly, when prescribing anti-diabetic medications, it's important to consider the impact a drug has on fueling cancer growth."

Type 2 diabetes has been linked to higher risks of pancreatic, colorectal, breast, liver and bile duct, bladder and endometrial cancers.

This study was published December 5 in Diabetes, Obesity and Metabolism.

Cleveland Clinic Lerner College of Medicine Research Programs funded portions of this research. One of the authors consults for Merck and GlaxoSmithKline and received support from Astra Zeneca. Another author is a speaker for Novo Nordisk.

Review Date: 
December 9, 2013