In 2009, there was much ado about the possible correlation between glargine and cancer in people with type 2 diabetes. Several studies published in Diabetologia indicated a relationship between different types of cancer and glargine. Therefore, investigators developed prospective studies to prove whether or not there was a causal relationship. The latest evidence- based literature has not demonstrated a causal link between glargine and cancer. This lack of relationships with specific cancers has clearly reduced anxiety regarding the potential effect of glargine on cancer. However, there have been concerns focusing on breast cancer, particularly with longer exposure to insulin. Keep in mind that there is a clear association between diabetes and the incidence of cancer that is not completely understood. Some sources include insulin resistance and obesity, age and smoking. Because glargine is the most commonly prescribed formulation of insulin, its safety is extremely important to people with all forms of diabetes.
The vast majority of my children and adolescents with diabetes are on basal/bolus therapy. A significant number of them use insulin pump therapy; however, large percentages continue to prefer multiple daily insulin injections with either Lantus or Levemir. Therefore, I am always on the alert for studies that may have significance for my patient population, especially those that may present problems in the future.
A recent study published ahead of print by Sturmer, Marquis, Zhou, et. al (John Buse –senior author) in Diabetes Care- Cancer Incidence among those initiating insulin therapy with glargine versus NPH Human Insulin (Diabetes Care DOI: 10.2337/dc13-0263) provides additional evidence in regard to NPH, Lantus and Cancer. The authors present the largest study to date that discusses the most important concerns raised by those 2009 publications, “In patients with diabetes who are initiating treatment with long acting insulins, how does cancer incidence compare in those initiated on insulin glargine versus NPH insulin (a non-analog form of insulin)?”
The study population consisted of patients with at least one diagnostic code for diabetes enrolled in a US health plan “covered by the Inovalon MORE Registry anytime between 1/1/2003 and 12/31/2010.” All patients under 18 years old were excluded. 43,306 and 9,147 patients were begun on glargine and NPH, respectively. (Therefore, it is likely that there were very few patients with type 1 diabetes)
Results indicated that “Initiators of glargine were followed for 1.2 (1.1) years and 50,548 (10,011) person-years; 993 (178) developed cancer, respectively. The overall HR (can you define HR?) was 1.12 (95% CI 0.95–1.32). Results were consistent for breast cancer, prostate cancer, and colon cancer; various durations of treatment; and sensitivity analyses.”
So we can conclude that patients initiating insulin glargine rather than NPH do not seem to be at an increased risk for cancer. These results were consistent for overall and specific cancers including breast, prostate, and colon cancer.
According to the authors, the study contributes to the evidence base for longer-term treatment with glargine; however, data for treatment beyond two years is limited due to the fact of patients not using glargine or NPH over prolonged periods of time rather than the lack of long-term observation of patients. Despite the fact that all forms of diabetes were captured with the diagnostic code for diabetes, the fact remains that approximately 90% of diagnosed diabetes is type 2. Thus, research is still required for our pediatric and adolescent population who will require some form of basal insulin if on multiple daily injections.
I will continue to keep you posted.
Published On: August 20, 2013