The purpose of this research is to determine the effects of Metformin, a well tolerated drug widely prescribed for treatment of Type 2 Diabetes Mellitus, on endometrium cancer patients.

Inclusion Criteria:

• Histological confirmed diagnosis of grade I or II adenocarcinoma of the endometrium

• Must be obese as defined by a body mass index (BMI) greater than or equal to 30 kg/m2

• Candidate for surgical removal of their uterus as part of their endometrial cancer treatment

• Subjects must have signed informed consent

• Age 42 - 65 years of age

• Electrocorticogram (ECOG) Performance status of 0 - 2

• History of adequate renal, liver, and bone marrow function:

  • Hb: (adequate for surgical intervention, with transfusion if necessary) White Blood Cell (WBC): (normal range)
  • Platelets: (180K/cmm)
  • Liver Function Test(LFTs): Normal bilirubin (<2.0mg/dL), AST/ALT (2xULN)
  • Renal function: creatinine less than 1.4

• Female subjects must either not be of child-bearing potential or must have a negative urine pregnancy test within 7 days of randomization to Metformin. Subjects are considered not of child-bearing potential if they are surgically sterile or they are postmenopausal for greater than 12 months.

Exclusion Criteria:

• Poorly differentiated cancer or any of the high-risk subtypes of endometrial cancer including serous, clear cell, or carcinosarcoma
• History of diabetes mellitus Type 1 or Type 2.
• Receiving metformin prior to enrollment
• Known hypersensitivity to metformin.
• Unable to swallow and retain oral medication.
• Pregnant or lactating.
• Previous or concurrent malignancies, except non-melanoma skin cancers, unless curatively treated and with no evidence of recurrence for > 5 years
• If the physician feels that the candidate is not suitable for the study, he/she will be excluded.
• Currently taking biguanides, sulfonylurea drugs, thiazolidinediones, insulin, or mTOR or DPP-4 inhibitors or having taken any of these medications during the 12 weeks prior to study participation.
• Clinical symptoms of gastrointestinal obstruction or bleeding and consideration for immediate surgery or immediate neoadjuvant chemoradiation.
• History of lactic or other metabolic acidosis.
• Uncontrolled infectious disease.
• History of positivity for human immunodeficiency virus (HIV).
• History of congestive heart failure requiring pharmacologic treatment.
• History of excessive alcohol abuse, defined by a habitual intake of more than three drinks daily.
• Mal-absorption syndrome, disease affecting gastrointestinal function, or previous resection of the stomach or small bowel.
• Current use of medications for weight loss.
• Currently taking cimetidine, thiazide diuretics or cephalexin. If a patient needs some of these agents, alternative agents should be substituted.