A Clinical Trial of Metformin in the Maintenance of Non-Hodgkin's Lymphoma Patients

Inclusion Criteria: 1. Male or female patient age \>14 years old; 2. Pathological types include: diffuse large B lymphoma, and stage III follicular lymphoma; 3. At the initial stage of therapy, received standard R-CHOP regimen and complete remission after the first course of treatment; 4. After complete remission, not consider to receive hematopoietic stem cell transplantation or chimeric antigen receptor T cell immunotherapy; 5. Serum glutamic-oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) not exceed 2 times of the normal upper limit; 6. Serum total bilirubin and creatinine not exceed 1.5 times of the normal upper limit; 7. Serum creatinine not exceed 1.5mg/dl; 8. Patients with high risk factors, including age \> 60 year, or with diabetes/ impaired glucose tolerance, or with International Prognostic Index (IPI) score ≥2. 9. Sign informed consent file. Exclusion Criteria: 1. Past medical history of high doses of cytarabine, methotrexate and rituximab maintenance therapy; 2. Past medical history of any type of hematopoietic stem cell transplantation; 3. Past medical history of lactic acidosis; 4. Extreme weight loss failure, malnutrition or dehydration patients; 5. Pregnant women or lactating women, or women who do not take contraceptive measures for childbearing age; 6. Alopecia, mental retardation or psychiatric disorders that affect the patient's normal informed consent; 7. Type 1.2 diabetes with ketoacidosis, liver function or renal insufficiency, pulmonary insufficiency, heart failure, acute myocardial infarction, severe infection and trauma, major surgery and clinical hypotension or hypoxia; 8. Diabetes complicated with severe chronic complications (such as diabetic nephropathy, diabetic retinopathy); 9. Any other serious complications occurred, depending on the outcome of the study; 10. Before the intravenous pyelography or anterior angiography; 11. Alcoholics; 12. Deficiency of Vitamin B12, folic acid or iron.