Metformin in Non Small Cell Lung Cancer (NSCLC)

Inclusion Criteria:

Patients with pathologic diagnosis of lung NSCLC or squamous cell carcinoma.
Patients are to be treated with hypofractionated RT.
Patient is not a surgical candidate due to medical comorbidities determined by a thoracic surgeon or patient refusal
Patient plans to receive treatment at MD Anderson
Patients must sign informed consent
Patient must have adequate renal function within 30 days prior to registration, defined as serum creatinine within normal institutional limits or creatinine clearance at least 60 ml/min

Exclusion Criteria:

Patient has: random glucose >200 mg/dl or is taking an oral hypoglycemic agent or insulin at the time of study entry
Patient has a history of lactic acidosis, chronic kidney disease or a creatinine >/= 1.2 mg/dl
Women who are pregnant or breast feeding, as treatment involves unforeseeable risks to the participant, embryo, fetus, or nursing infant
Patients with history of allergic reaction to metformin