I think we have all heard the advertisements on television warning that certain diabetes drugs (such as actos) causes bladder cancer. Are these warnings valid?
That’s a good question. It is important to take good care of your diabetes, but you don’t want to do so at the cost of developing cancer. Do certain diabetes drugs increase the risk of getting cancer? The answer is that we don’t know. Having type 2 diabetes increases risk of developing certain types of cancer, as does being obese. In 2009, some articles were published raising concern that insulin glargine (Lantus) causes cancer. Last year, the results of the ORIGIN (Outcome Reduction with Initial Glargine Intervention) study were published. The study was conducted over the course of six years and included thousands of subjects. Those who were treated with glargine had no increased risk of cancer. The answer is less clear for pioglitazone (Actos). There is some evidence that it does increase the risk of developing bladder cancer, but the evidence is not conclusive. Where increased risk has been shown, it has increased with cumulative dose. This suggests that by keeping the dose low and not taking the medication for a long time, one can avoid or at least minimize the increased risk. The story is even less clear when it comes to incretin-based therapies. These include the glucagon-like peptine-1 (GLP-1) agonists Byetta, Victoza, and Bydureon as well as the dipeptidyl peptidase-4 (DPP-4) inhibitors diabetes pills Januvia, Onglyza, and Tradjenta. The DPP-4 inhibitors work by a mechanism that is similar to that of the GLP-1 agonists. There is some evidence that both classes of medications may increase the risk of acute pancreatitis and possibly pancreatic cancer. Even if the medications are associated with these conditions, however, that does not tell us that the medications are the cause. Each of these medicines is used only by people with type 2 diabetes. Type 2 diabetes is associated with increased risk of acute pancreatitis and pancreatic cancer. While some other diabetes medicines cause weight gain, GLP-1 agonists are typically associated with weight loss and DPP-4 inhibitors are weight-neutral. For this reason, these medicines are used more often in patients who are obese. Obesity is associated with acute pancreatitis and pancreatic cancer. The good news is that we may get an answer in the near future. The U.S. Food and Drug Administration (FDA) recently announced that it is reviewing data on this topic. The FDA will participate in the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and National Cancer Institute’s (NCI) Workshop on Pancreatitis-Diabetes-Pancreatic Cancer in June of this year and will share their conclusions once they are reached.