Patients with type 2 diabetes are known to be at higher risk for several types of cancers. A new study found this risk to be especially high in those being treated with drugs that stimulate insulin production, and suggests that other diabetic medications that naturally raise insulin levels, like metformin — along with the use of statins — work to counteract such risk.
The study, “Use of statins offsets insulin-related cancer risk,” published in the Journal of Internal Medicine, specifically shows that patients taking diabetes therapies — such as insulin or insulin secretagogues — are at much higher risk of pancreatic cancer, while metformin actually played a protective role against prostate cancer and certain lymphomas.
“In the present study, we observed a lower risk of various cancers in patients receiving statins. Signiﬁcant effects were found for all agents except lovastatin in both sexes,” the researchers wrote. “Remarkably, we were able to show that the protective effect of statins more than offsets the increased cancer risks due to insulin-providing therapies.”
The team, led by Alexandra Kautzky-Willer, MD, from the Medical University of Vienna, examined all possible associations between type 2 diabetes, statin use, and site-specific cancers, using data from all patients with medical stays in Austria during 2006 and 2007, accounting for a total of almost 1.85 million patients, of whom about 1.06 million were women.
“We found higher cancer risks in patients treated with insulin-providing drugs for liver, lung, and secondary neoplasms in male patients, and for pancreas in both sexes, but a lower risk for prostate cancer in men,” they wrote.
Indeed, insulin was found to induce a 4.5-fold and 4.2-fold increase in the risk of pancreatic cancer in men and women, respectively, which was one of the strongest effects observed among all therapies and site-specific cancers.
Other treatments, such as sulfonylureas, which increase the amount of insulin produced by the pancreas, were also seen to increase the risk for specific cancers, including cancers of the larynx, rectum, liver, and pancreas, as well as leukemias, in both men and women. The strongest effect, however, was seen in skin cancer, with sulfonylureas nearly tripling the risk of this type of cancer in both man and women.
Glitazones, however, which improve the use of insulin by the body without increasing insulin levels, decreased the risk of skin cancer by nearly half.
Similarly, metformin (marketed as Glucophage, among others), which works by helping to restore the body’s proper response to the naturally produced insulin, showed a protective effect in several cancers, including larynx, prostate and pancreas, and for lymphoid leukemia. However, the strongest protective effect of metformin was seen in prostate cancer (18% risk reduction), and non-Hodgkin’s lymphoma (24% risk reduction).
“These ﬁndings suggest that different antihyperglycaemic drugs modify the diabetes-related and site-speciﬁc cancer risks in different ways,” the researcher wrote, adding that therapies that increase the body’s responsiveness to that naturally produced insulin and that do not increase insulin levels should be the preferred treatment choices.