Metformin and/or TZDs (thiazolidinediones) may undermine the progression of lung cancer, as well as improve survival rates and reduce the risk of advanced lung cancer for patients with both diabetes and lung cancer, researchers from The Cleveland Clinic explained at the 76th annual meeting of the American College of Chest Physicians – Chest 2010.

Study leader, Peter Mazzone, MPH, MD, FCCP, said:

Our study, as well as other research, suggests an association between metformin and/or TZDs use and the risk of developing lung cancer. 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.

Dr. Mazzone and team set out to find out what impact metformin and TZDs might have on lung cancer presentation and its progression. They examined the medical records of 157 patients – they all had diabetes as well as a history of lung cancer. They gathered information on where they lived, age, sex, marital status, family size, education, occupation – collectively known as “demographics – as well as their smoking history, what diabetes drugs they used, and lung cancer data (cancer stage, histologic findings and survival).

They compared lung cancer characteristics between those who had taken metformin/TZDs before lung cancer diagnosis (metformin/TZD group) and those who hadn’t (the other group).

The researchers found that:

  • Those in the metformin/TZD group had a 20% risk of developing metastasis or a small cell or squamous cell carcinoma.
  • Those in the other group had a 42.4% risk of developing metastasis or a small cell or squamous cell carcinoma.
  • Patients in the metformin/TZD group had a better survival rate versus those in the other group
  • Patients who had used either TZDs or metformin before a lung cancer diagnosis had similar ages, smoking histories and gender ratios.

Dr. Mazzone said:

The initial trend we have seen is toward metformin being more protective than TZDs. 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 researchers explain that diabetes medications, such as metformin may have a significant role to play in lung cancer therapy. Diabetes Type 2 affects tens of millions of Americans, many of whom don’t know they have the disease. In 2008 over 41 million metformin prescriptions were written in the USA; it is one of the most common diabetes type 2 medications.

President of the American College of Chest Physicians, David Gutterman, MD, FCCP, said:

This new information adds to the growing body of evidence that metformin may help prevent and inhibit the progression of lung cancer. However, more studies are needed before any changes in the standard treatment for lung cancer can be proposed.

Source: Chest 2010 76th annual meeting of the American College of Chest Physicians

Written by Christian Nordqvist