Contrary to an earlier epidemiological study, rosiglitazone use is not associated with an increased risk of developing cancer, according to a new report.
Dr. Edoardo Mannucci from Azienda Ospedaliero-Universitaria Careggi in Florence, Italy stated that, "Based on clinical trials, rosiglitazone does not increase the risk of cancer." "It is possible that prolonged exposure to this drug protects from cancer, but this hypothesis needs to be confirmed by longer-term trials."
Dr. Mannucci and colleagues performed a meta-analysis of randomized clinical trials to assess the risk of cancer associated with rosiglitazone treatment, compared with placebo or active hypoglycemic drugs.
There was no difference in incident malignancies between patients allocated to rosiglitazone versus other agents or placebo, the authors report.
The results were similar for nondiabetic and type 2 diabetic patients, for different comparators, and for the most common cancer types analyzed separately, the researchers note.
In fact, the investigators say, the cumulative incidence density of cancer was significantly lower in the rosiglitazone group than in the comparator group.
"A recent epidemiological study had shown an increased risk of cancer associated with rosiglitazone, but the risk was not adjusted for relevant confounders; in fact, obese, insulin-resistant, hyperinsulinemic patients, who are at greater risk for cancer, have a greater chance of receiving thiazolidinedione treatment, and this produces an association between drug use and incident malignancies," Dr. Mannucci explained. "Conversely, some experimental data suggested that thiazolidinediones could have a protective effect; however, longer term trials would be needed to assess this benefit."
"We will perform epidemiological studies on a clinical sample of type 2 diabetic patients, who have been thoroughly studied for many parameters, allowing multiple adjustments," Dr. Mannucci said. "Unfortunately, the use of thiazolidinediones has been very scarce in our country, due to restrictions on prescriptions which have been removed only recently. This means that we will have to wait for some years before we are capable of producing further data on this subject."
Diabetes Care 2008;31:1455-1460.