Greater risk reduction in those not receiving antihyperglycemic treatment.
The purpose of this study was to see if the use of statins could offset insulin-related cancer risk for patients with type 2 diabetes mellitus (T2DM).
Diabetes mellitus and cancer are common conditions, and their co-diagnosis in the same individual is not infrequent. The relative risks associated with type 2 diabetes are greater than twofold for hepatic, pancreatic, and endometrial cancers. The relative risk is somewhat lower, at 1.2–1.5-fold for colorectal, breast, and bladder cancers. In comparison, the relative risk of lung cancer is less than 1. The evidence for other malignancies (e.g. kidney, non-Hodgkin lymphoma) is inconclusive, whereas prostatic cancer occurs less frequently in male patients with diabetes. The potential biologic links between the two diseases are incompletely understood. Evidence from observational studies suggests that some medications used to treat hyperglycemia are associated with either increased or reduced risk of cancer. Whereas anti-diabetic drugs have a minor influence on cancer risk, drugs used to treat cancer may either cause diabetes or worsen pre-existing diabetes. If hyperinsulinemia acts as a critical link between the observed increased cancer risk and type 2 diabetes, one would predict that patients with type 1 diabetes would have a different cancer risk pattern than patients with type 2 diabetes because the former patients are exposed to lower levels of exogenously administered insulin. Obtained results showed that patients with type 1 diabetes had elevated risks of cancers of the stomach, cervix, and endometrium. Type 1 diabetes is associated with a modest excess cancer risk overall and risks of specific cancers that differ from those associated with type 2 diabetes.
Alexandra Kautzky-Willer, M.D., from the Medical University of Vienna, and colleagues characterized all possible associations between individual T2DM therapies, statin use, and site-specific cancers in the Austrian population using medical claims data for 1,847,051 patients with hospital stays during 2006 to 2007.
The researchers found that the risk of cancers of the colon (males only), liver (males only), pancreas, lung (males only), and brain (males only) were increased up to nine-fold for patients treated with insulin or insulin secretagogues; the risk of prostate cancer was decreased strongly.
The risks were generally decreased for patients taking statins, with a greater risk reduction among those not receiving antihyperglycemic therapies. The effects were strongest for use of insulin and pancreatic cancer, sulfonylureas or glitazones and skin cancer, and metformin and prostate cancer, corpus uteri, and non-Hodgkin’s lymphoma.
The authors wrote that, “Overall, our data support the hyperglycemia-cancer hypothesis…. Therefore, insulin-sparing and insulin-sensitizing drugs should be the preferred treatment choices.”
- Risk of cancers were increased up to nine-fold for patients treated with insulin or insulin secretagogues.
- In patients taking statins, the risks were generally decreased, with a greater risk reduction in patients not receiving antihyperglycemic therapies.
- The use of statins offsets insulin-related cancer risks in patients with diabetes independently of sex and age.
Published online Oct. 21 in the Journal of Internal Medicine.