Conditions: Breast Neoplasms
Keywords: Obesity Survival Weight loss Metformin Biological markers
Allocation: RANDOMIZED | Intervention model: FACTORIAL
Enrollment: 333
Healthy volunteers: no

Brief summary:
This objective of this randomized controlled trial is to conduct a 2x2 test of a lifestyle intervention and metformin (a drug used to treat diabetes) to investigate how these treatments, alone or in combination, affect biomarkers associated with breast cancer survival. The Reach for Health Study will enroll 340 overweight/obese, postmenopausal breast cancer survivors. After completing the screening process and baseline measures, participants will be randomized in equal numbers to: (1) placebo, (2) metformin, (3) lifestyle intervention and placebo, or (4) lifestyle intervention and metformin. The intervention was powered on the main effects and the planned analyses are to compare: Metformin to Placebo and a separate comparison of Lifestyle intervention to control. The interventions will last for 6 months. Concentrations of circulating biomarkers will be assessed at baseline and 6 months.

Detailed description:

Arms:
arm 1: None arm 2: None arm 3: None arm 4: None

Interventions: intervention 1: Metformin intervention 2: Placebo intervention 3: Lifestyle intervention intervention 4: Standard printed dietary guidelines
Intervention descriptions: intervention 1: Week 1: 500 mg at dinner time Weeks 2-4: 1000 mg at dinner time Weeks 5+: 500 mg in morning; 1000 mg at dinner time intervention 2: Week 1: 1 pill at dinner time Weeks 2-4: 2 pills at dinner time Weeks 5+: 1 pill in morning; 2 pills at dinner time intervention 3: Telephone-based lifestyle intervention (dietary change and physical activity) for weight loss. intervention 4: Set of standard health education materials provided to participants at single time point (immediately after randomization)

Protocol document: