THURSDAY, April 21 (HealthDay News) -- Pioglitazone does not appear to be associated with common cancers in people with diabetes, though there may be an increased risk for bladder cancer in those who have received more than two years' treatment with the agent, according to two articles published in the April issue of Diabetes Care.
Assiamira Ferrara, M.D., Ph.D., of Kaiser Permanente Northern California in Oakland, and colleagues conducted a cohort study of 252,467 patients with diabetes aged 40 and over to explore the possible association between pioglitazone and cancers at 10 common sites: prostate, breast, lung, endometrial, colon, non-Hodgkin lymphoma, pancreas, kidney, rectal, and melanoma. They found no clear evidence for such an association, but noted longer-term studies (six years or longer) are needed.
James D. Lewis, M.D., of the University of Pennsylvania in Philadelphia, and colleagues examined outcomes in 193,099 patients with diabetes age 40 and over, 30,193 of whom were treated with pioglitazone, to investigate a possible link between the drug and an increased risk of bladder cancer. They determined that, overall, the drug was not associated with a risk of bladder cancer, but in a group treated with the drug for more than two years, there was a weak association of increased risk.
"Additional follow-up is planned to explore this association. Regardless, it is reassuring that only three of the 90 patients diagnosed with bladder cancer and treated with pioglitazone were at advanced stage," Lewis and colleagues conclude.
Several authors of both studies disclosed financial relationships with pharmaceutical companies, including Takeda, which funded the studies.