A class of drugs called thiazolidinediones has been linked to an increased risk of bladder cancer among adults with type 2 diabetes, according to a study published early online in the Canadian Medical Association Journal.
Bladder cancer is diagnosed in as many as 60,000 individuals annually in the United States. It is much more common in elderly individuals. Individuals with type 2 diabetes have a 40 percent increased risk of bladder cancer. What’s more—some research has indicated that individuals who take pioglitazone, a type of thiazolidinedione, have a higher incidence of bladder cancer.
To evaluate the relationship between thiazolidinediones and bladder cancer, researchers conducted a systematic review and meta-analysis of randomized controlled trials and observational studies involving over 2.6 million patients. They observed an increased risk of bladder cancer associated with the use of thiazolidinediones, particularly pioglitazone.
The researchers concluded that there is some limited evidence to indicate that thiazolidinediones, and particularly pioglitazone, are associated with an increased risk of bladder cancer among adults with type 2 diabetes. The researchers note that although the risk is small, it may provide good reason to use other equally effective treatments for type 2 diabetes that don’t carry an increased risk of cancer.
Colmers IN, Bowker SL, Majumdar SR, Johnson JA. Use of thiazolidinediones and the risk of bladder cancer among people with type 2 diabetes: a meta-analysis. Canadian Medical Association Journal. Published early online July 3, 2012 DOI: 10.1503/cmaj.112102