Do we have enough data to confirm the link between antidiabetic drug use and cancer development?

Diabetes, especially type 2, is associated with higher risk of certain types of cancer. Potential mechanisms underlying increased cancer risk in diabetics remain unclear. Insulin resistance, hyperinsulinemia, oxidative stress, advanced glycation end products, and chronic low-grade inflammation have been suggested. Interestingly, recent epidemiological studies have also reported an association between cancer incidence and antidiabetic drug therapy. The available data, although inconclusive, may suggest higher cancer risk in patients treated with some hypoglycemic medications (e.g., insulin and sulfonylureas). On the other hand, metformin and rosiglitazone may inhibit cancer progression, especially in breast cancer. In this review, we aim to discuss the current knowledge about this important clinical issue.