Individual risk still remains low, even though, people with type 2 diabetes have a 40 percent increased risk of developing bladder cancer. This increased risk is believed to be associated with high levels of insulin found in people with type 2 diabetes….
There’s more evidence that people with type 2 diabetes may have an increased risk of bladder cancer, and taking the diabetes drug Actos may raise that risk even higher.
Taking pioglitazone (brand name Actos) raised the risk of bladder cancer by about one-fifth, according to a new analysis of previously completed studies. However, the individual risk of getting bladder cancer still remained quite low.
Senior author Jeffrey A. Johnson, the Canada Research Chair in Diabetes Health Outcomes at the University of Alberta School of Public Health, in Canada stated that, “The evidence suggests that this drug is associated with about a 22 percent increased risk of bladder cancer.”
This isn’t the first time the drug has been associated with heightened odds for bladder cancer: A study published May 31 in BMJ found that taking Actos for two years can double the risk.
Johnson said it’s not clear yet how Actos might raise the risk of bladder cancer, but he said some animal studies suggested that the drug could cause crystals to form that irritate the bladder, which could potentially play a role in the development of bladder cancer.
In the current analysis, Johnson and his colleagues reviewed the available data on thiazolidinediones and bladder cancer in type 2 diabetes. They included 10 studies in their analysis that had more than 2.6 million people. From that group, 3,643 people were newly diagnosed with bladder cancer.
Not all of the studies found a link between Actos and bladder cancer. One randomized controlled trial, which is the type of study considered the “gold standard” for such research, found no association. However, the other studies combined found a 15 percent increase in the risk of bladder cancer with the use of thiazolidinediones, which the authors attribute to the use of Actos. Overall, they found a 22 percent increased risk of bladder cancer with the use of Actos.
Johnson added that it’s important to keep in mind that bladder cancer is a relatively rare cancer, and even with the increased risk, any one person’s risk of bladder cancer “is pretty small.”
Canadian Medical Association Journal, July 3, 2012.