"Commonly used diabetes drugs such as metformin may help control lung cancer and may help prevent it U.S. researchers reported on Tuesday.  An Xray of a chest showing a growth on the left side of the lung in an undated image. REUTERSNIHHandout Patients who had taken the drugs to control diabetes were much less likely to have lung cancer spread  which is when it becomes most deadly  the researchers told a meeting of the American College of Chest Physicians.  Metformin an older and cheaper drug available generically had a more powerful effect than newer drugs called thiazolidinediones TZDs or glitazones the researchers said.  Our study as well as other research suggests an association between metformin andor TZD use and the risk of developing lung cancer said Dr. Peter Mazzone of the Cleveland Clinic in Ohio who led the study.  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 andor TZDs.  The team reviewed the medical records of  lung cancer survivors with diabetes.  Those who had taken either a metformin drug or a TZD were significantly less likely to have advanced lung cancer that had spread   percent of those who took the drugs had tumors that had spread versus  percent of those who had not.  The initial trend we have seen is toward metformin being more protective than TZDs Mazzone said.  TZDs include GlaxoSmithKlines Avandia known generically as rosiglitazone and rival drug Actos or pioglitazone made by Takeda Pharmaceutical Co Ltd.  Mazzone said it may be possible one day to use metformin to prevent lung cancer in smokers.  But Dr. David Gutterman president of the American College of Chest Physicians said more research would be needed before this could be proposed.  This new information adds to the growing body of evidence that metformin may help prevent and inhibit the progression of lung cancer Gutterman said.  Metformin is one of the most widely used drugs for type  diabetes with  million prescriptions written in the United States in  the American College of Chest Physicians said in a statement.  In May researchers reported an inhaled drug called iloprost approved to treat pulmonary hypertension might also prevent lung cancer.  In April researchers said a natural supplement derived from food called myoinositol seems to stop the precancerous changes that lead to lung cancer.  Lung cancer is the No.  cancer killer globally killing . million people a year. Only  percent of people diagnosed with lung cancer are still alive five years later in part because the disease usually spreads silently for years before it causes clear enough symptoms to be detected.  Early stage lung tumors can often be removed surgically however.  The World Health Organization estimates  million people globally had diabetes in  and predicts that number will nearly double by  to  million."