Insulin Type May Not Boost Cancer Risk

Type 2 diabetes patients starting insulin glargine did not have increased risk of cancer

(RxWiki News) Some patients with type 2 diabetes need an extra boost of insulin from the outside to get their blood sugar under control. Researchers wanted to see if one insulin treatment option carries a risk of cancer.

Patients taking insulin glargine - a type of insulin that works for up to 24 hours - do not seem to have a higher risk of cancer than those taking other long-acting insulin treatments.

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In a recent study, Jean-Paul Fagot, PharmD, of the Strategy and Research Department of National Health Insurance in France, and colleagues asked if there was a cancer risk associated with taking insulin glargine.

Insulin is a natural hormone made by the pancreas that helps manage levels of sugar in the blood. In type 2 diabetes, the body does not respond well to insulin, which leads to higher blood sugar levels.

To control blood sugar throughout the day, some diabetes patients are given background or basal insulins, including insulin glargine. Unlike other insulin treatments, basal insulins work continuously, which is similar to how a healthy pancreas makes insulin.

From their study, Dr. Fagot and colleagues found that type 2 diabetes patients taking insulin glargine did not have an increased risk of all cancers nor of breast cancer, compared to patients taking other basal insulins.

The overall cancer rate among patients taking insulin glargine was 1,622 per 100,000 person years. Among those taking other basal insulins, the cancer rate was 1,643 per 100,000 person years.

The researchers found no link between insulin glargine use and overall cancer risk, with a hazard ratio of 0.97.

A hazard ratio explains how often an event happens in one group versus another. A hazard ratio of less than 1.0 means that event happens in one group less than the other group.

In this case, the hazard ratio of 0.97 means that cancer occurred less often in glargine users than in other basal insulin users. However, the difference was not significant.

The results also showed no significant link between insulin glargine use and breast cancer risk, with a hazard ratio of 1.08.

Again, this hazard ratio does not show a large difference in risk.

Because the study did not follow patients for more than 4 years, more research is needed to understand the longer-term risks of taking insulin glargine, the authors said.

The study included 70,027 patients between 40 and 79 years of age who started basal insulin treatment between 2007 and 2009.

The research was published September 10 in Diabetes Care, a journal of the American Diabetes Association. 

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Review Date: 
September 16, 2012