"Diabetic patients should discuss bladder cancer with their MD."
Researchers from the Perelman School of Medicine at the University of Pennsylvania analyzed 60,000 people with Type 2 diabetes. They were all patients of the Health Improvement Network (THIN) database in the United Kingdom.
People who had been treated with the TZD drugs Actos (pioglitazone) or Avandia (rosiglitazone) for 5 or more years, had 2-3 fold greater risks of developing bladder cancer than patients taking the sulfonylurea drugs.
Most patients in this country no longer take Avandia since it has been linked to severe heart problems.
For some unknown reason, people with diabetes are already more prone to bladder cancer than individuals who don’t have the condition.
The study found that 170 patients per 100,000 taking TZDs are expected to develop bladder cancer, compared with only 60 people in every 100,000 patients taking the sulfonylurea drugs. This compares to 30 people per 100,000 in the normal population who develop bladder cancer and 40 cases for every 100,000 people with diabetes.
The study’s lead author, Ronac Mamtani, MD, an instructor in the division of Hematology-Oncology in Penn’s Abramson Cancer Center, said in a press release, “Our study shows that doctors who care for patients with diabetes should be very aware of any bladder-related symptoms patients might be having, like blood in the urine, and take steps to further evaluate those issues.”
Actos is the ninth most commonly drug prescribed in the United States, with about 15 million prescriptions be written for it every year. It’s designed to treat diabetics who no longer respond to Metformin.
The drug is no longer available in France and Germany and the U.S. Food and Drug Administration has warned about its association with bladder cancer.
“The risk does seem to be common among both drugs in the TZD class, and the fact that we have compared bladder cancer risk among patients taking each of those drugs provides essential information, because a safety warning on a drug is only useful to a doctor when they have knowledge of the same risks for an alternative drug,” Dr. Mamtani said.
This research, funded by the National Institutes of Health, was published in August issue of the Journal of the National Cancer Institute.