Metformin Hydrochloride in Preventing Esophageal Cancer in Patients With Barrett Esophagus

Inclusion Criteria

• Histologically confirmed diagnosis of Barrett esophagus, with no dysplasia, indeterminate for dysplasia, or low-grade dysplasia as defined by the presence of specialized columnar epithelium on histology and >= 2 cm of involvement on endoscopy
• Adequate Barrett mucosa, which is defined as >= 1 out of 4 research samples (i.e., >= 25%) with >= 50% intestinal metaplasia in biopsies required to satisfy the endpoints of the study
• No history of esophageal carcinoma or other cancer(s) (except for non-melanoma skin cancers)
• No erosive esophagitis or ulcerative esophagitis, unless treatment with a proton pump inhibitor (PPI) results in healed erosions or ulcers prior to entry endoscopy
• No history of high-grade dysplasia or cancer (confirmed locally by esophagogastroduodenoscopy [EGD] and Pathology reports)
• No ulcer, plaque, nodule, stricture, or other luminal irregularity within the Barrett segment, unless clinical biopsy produces no evidence of high-grade dysplasia or cancer
• ECOG performance status = = 10 g/dL
• Leukocytes >= 3, 000/mL (>= 2,500/mL for African-American participants)
• Absolute neutrophil count >= 1, 500/mL (>= 1,000/mL for African-American participants)
• Platelets >= 100,000/mL
• Total bilirubin = = 3 drinks per day)
• No kidney disease or renal insufficiency (defined as serum creatinine outside the normal institutional limits)
• Currently on a proton pump inhibitor (PPI) >= 4 weeks (any PPI taken at least once daily is acceptable)
• No medication(s) for weight loss ≤ 2 months prior to Pre-Registration
• No treatment with medications that may increase metformin hydrochloride levels: cationic drugs, e.g., digoxin, amiloride, procainamide, ranitidine, trimethoprim, quinidine, quinine, vancomycin, triamterene, and morphine
• No treatment with other oral hypoglycemic agents
• No participant use of metformin, cimetidine (Tagamet), furosemide (Lasix), or nifedipine (Cardizem), or any other drug contraindicated for use with metformin
• No receipt of any other investigational agents =< 3 months prior to Pre-Registration, except innocuous agents with no known interaction with the study agent (e.g., standard dose multivitamins or topical agents for limited skin conditions), at the discretion of the Protocol Lead Investigator at each Participating Site
• No participants who have undergone ablation or other local therapies (e.g., percutaneous dilatational tracheostomy [PDT], cryotherapy, radiofrequency, argon plasma coagulation [APC], or multipolar electrocoagulation [MPEC])
• Patients treated with endoscopic mucosal resection [EMR] allowed
• No participants anticipating elective surgery during the study period
• No participants planning to undergo elective radiologic studies involving intravascular administration of iodinated contrast materials