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Are you a 
former smoker?

I have liver cirrhosis: Welcome

Lung cancer, specifically non-small lung cancer (NSCLC), is the most common cause of cancer-related deaths and second most common cancer overall in the United States. Former tobacco smokers are at 6-fold higher risk for lung cancer compared to non-smokers. Ways to help protect high-risk individuals are needed. We are seeing if Metformin Extended Release (ER) has preventive and protective effects that can lower this risk.

Testing Metformin to lower lung cancer risk in high-risk individuals

Principal Investigators: 
Sai Yendamuri, MD - Roswell Park Comprehensive Cancer Center
Robert L. Keith, MD - Rocky Mountain Regional VA Medical Center
Stephen Lam, MD - University of British Columbia, BC Cancer Research Centre

Metformin ER has been widely used in the US since 1995 and is FDA approved to treat Diabetes Mellitus. Participants will undergo a bronchoscopy, a medical procedure to look into your lungs, and will then be placed into one of two groups based on random chance. Group 1 will receive up to 2000 mg of metformin orally once daily for up to 26 weeks. Group 2 will wait 6 months, undergo another bronchoscopy, and then receive up to 2000 mg of Metformin ER orally once a day for 26 weeks. Participants in both groups will undergo a final bronchoscopy after finishing their study medication. (Note: people in group 2 will undergo 3 bronchoscopies). This will allow researchers to see if participants taking Metformin ER show changes in their lungs, which may indicate a lower risk of developing cancer. This study is looking for volunteers who are 18 years of age or older, overweight, or obese and that are former smokers. About 50 participants will be enrolled. Participants will receive $150 for completing the baseline visits (including bronchoscopy), $50 for each non-bronchoscopy study visit and $150 for each bronchoscopy study visit for their time, transportation, parking, and other expenses related to the study.


You may be eligible if you:

  • Have quit smoking at least 12 months prior to enrollment.

  • Have a BMI greater than or equal to 25 with no prior diagnosis of Diabetes Mellitus (DM1 or DM2).

  • You have not used Metformin within the past 2 years.


If you think you may be eligible, you can contact a study coordinator at your preferred location from the list below:

ROSWELL PARK COMPREHENSIVE CANCER CENTER Emily Horn: (716) 845-1300, ext. 6967, - Buffalo, New York


UNIVERSITY OF BRITISH COLUMBIA, BC CANCER RESEARCH CENTRE Sukhinder Khattra: (604) 675-8089 – Vancouver, Canada

More Information:

Additional Resources

Study Brochure

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