Effect of Exercise or Metformin on Biomarkers of Inflammation in Breast and Colorectal Cancer: A Randomized Trial.

Observational studies report that physical activity and metformin are associated with improved clinical outcome in patients with cancer. Inflammation is one biological mechanism hypothesized to mediate these associations. In this phase II, multicenter, 2 × 2 factorial trial, 139 patients with breast and colorectal cancer who completed standard therapy were randomized to one of four treatment groups for 12 weeks: exercise alone, metformin alone, exercise and metformin, or control.

Randomized Phase II Trial of Exercise, Metformin, or Both on Metabolic Biomarkers in Colorectal and Breast Cancer Survivors.

Background: Observational data support inverse relationships between exercise or metformin use and disease outcomes in colorectal and breast cancer survivors, although the mechanisms underlying these associations are not well understood.

Methods: In a phase II trial, stage I-III colorectal and breast cancer survivors who completed standard therapy were randomly assigned to structured exercise or metformin or both or neither for 12 weeks. The primary outcome was change in fasting insulin levels; secondary outcomes included changes in other blood-based energetic biomarkers and anthropometric measurements.