POPULAR DIABETES DRUG MAY PROTECT AGAINST LUNG CANCER PROGRESSION

(VANCOUVER, BC, CANADA, November 2, 2010)—The popular diabetes drug, metformin, may also have a protective effect on the progression of lung cancer. New research presented at CHEST 2010, the 76th annual meeting of the American College of Chest Physicians (ACCP), finds an association between the use of metformin and/or thiazolidinediones (TZDs) and a lower risk of advanced lung cancer, as well as improved survival rate, among patients with diabetes who developed concomitant lung cancer.

"Our study, as well as other research, suggests an association between metformin and/or TZDs use and the risk of developing lung cancer," said lead study author Peter Mazzone, MPH, MD, FCCP, Cleveland Clinic, Ohio. "However, unique to this study, we have been able to report less advanced cancer in those who do develop cancer, a decreased frequency of squamous cell and small cell carcinomas, and improved survival, when controlled for stage, in people taking metformin and/or TZDs."

To determine the influence of metformin and TZDs on lung cancer presentation and course, Dr. Mazzone and colleagues reviewed the medical records of 157 patients with diabetes who had a history of lung cancer. Data collected included demographics, smoking history, diabetic medication use, and lung cancer characteristics (stage at presentation, histologic findings, survival). Lung cancer characteristics were compared between the group that had been exposed to metformin and/or TZDs prior to their lung cancer diagnosis and those who had not received either of the medications prior to their lung cancer diagnosis.

Patients who were exposed to either of the drugs were significantly less likely to have metastatic disease (20 percent vs 42.4 percent) or a small cell or squamous cell carcinoma. They also demonstrated improved survival (hazard ratio, 0.56). There were no significant differences between the age, sex, and smoking histories of the group exposed to metformin or TZDs prior to their lung cancer diagnosis.

"The initial trend we have seen is toward metformin being more protective than TZDs," said Dr. Mazzone. "The findings from our completed study may lead to chemoprevention studies in at-risk groups, and, possibly, trials that add one or both of these medications to standard treatment."

The potential impact of diabetes drugs, such as metformin, on the treatment of patients with lung cancer is significant. Millions of Americans have been diagnosed with type 2 diabetes, and many more are unaware they are at high risk. Metformin is one of the most widely used drugs for type 2 diabetes, with 41 million prescriptions written in the United States in 2008.

"This new information adds to the growing body of evidence that metformin may help prevent and inhibit the progression of lung cancer," said David Gutterman, MD, FCCP, President of the American College of Chest Physicians. "However, more studies are needed before any changes in the standard treatment for lung cancer can be proposed."

CHEST 2010 is the 76th annual meeting of the American College of Chest Physicians, held October 30 - November 4 in Vancouver, BC, Canada. The ACCP represents 18,000 members who provide patient care in the areas of pulmonary, critical care, and sleep medicine in the United States and throughout the world. The mission of the ACCP is to promote the prevention, diagnosis, and treatment of chest diseases through education, communication, and research. For more information about the ACCP, please visit the ACCP Web site at www.chestnet.org.