title: Metformin intervention in obese non-diabetic patients with breast cancer: phase II randomized, double-blind, placebo-controlled trial.
abstract: Previous observational studies have suggested that metformin in diabetes patients may reduce breast cancer risk more than the reductions from other anti-diabetes medications. This randomized, double-blind, placebo-controlled trial was performed to evaluate the efficacy of metformin for controlling physical and metabolic profiles related to prognosis and adverse events in non-diabetic breast cancer patients. Female breast cancer patients (N = 105), at least 6 months post-mastectomy, with obesity (≥25 kg/m(2)) and/or pre-diabetes (fasting blood sugar levels ≥100 mg/dL), were randomly assigned to three groups (placebo, metformin 500 mg, and metformin 1000 mg) stratified by tamoxifen use. A linear mixed model for repeated measurements among three groups and ANOVA for profile differences during 6 months of treatment were used for the intention-to-treat analysis. The metformin 1000 mg group had a significantly greater decline in glucose and HbA1c levels between treatment weeks 0 and 6 month (p = 0.008 and 0.009, respectively), and the declines increased with an increase in body mass index (BMI) level (p interaction with BMI = 0.007 and 0.067, respectively). A marginally significant different effect from the metformin 1000 mg treatment was detected for glucose and HbA1c levels (p interaction = 0.084 and 0.063, respectively) in the intention-to-treat analysis. Metformin 1000 mg treatment had a favorable effect on controlling glucose and HbA1C levels in obese non-diabetic breast cancer patients, indicating prognostic importance. Further trials are needed to elucidate the risk-benefit ratio of long-term use of metformin.
authors: Department of Preventive Medicine, Gacheon University College of Medicine, Inchon, Republic of Korea.
authors: Kwang-Pil
authors: KP
authors: Ko
authors: Seung Hyun
authors: SH
authors: Ma
authors: Jae-Jeong
authors: JJ
authors: Yang
authors: Yunji
authors: Y
authors: Hwang
authors: Choonghyun
authors: C
authors: Ahn
authors: Young-Min
authors: YM
authors: Cho
authors: Dong-Young
authors: DY
authors: Noh
authors: Byung-Joo
authors: BJ
authors: Park
authors: Wonshik
authors: W
authors: Han
authors: Sue K
authors: SK
authors: Park
mesh_terms: D015415:Biomarkers; D001943:Breast Neoplasms / Q000150:complications* / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D008687:Metformin / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D009367:Neoplasm Staging; D009765:Obesity / Q000150:complications*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D007004:Hypoglycemic Agents; D008687:Metformin