The primary goal of this project, co-led by Jeffrey Meyerhardt, MD, MPH, and Jennifer Ligibel, MD, is to examine whether a behavioral intervention aimed at increasing physical activity and metformin, alone or in combination, can reduce the levels of fasting insulin in colorectal cancer survivors.
The specific aims are:
- to examine the individual and joint effects of these interventions on C-peptide, IGF-I, and other biomarkers of this metabolic pathway
- to assess body composition by use of dual X-ray absorptiometry
- to assess diet quality and markers of inflammation
- to determine whether the theoretical constructs of planned behavior can predict change in exercise behavior in colorectal cancer survivors
Observational evidence suggests that factors related to energy balance, including exercise, body weight and diet, may be related not only to the risk of developing colorectal cancer, but also to prognosis in patients who develop the disease. Several studies have demonstrated that colon cancer risk and recurrence rates are elevated in individuals with higher circulating levels of insulin or C-peptide as well as in individuals with higher levels of insulin-like growth factor (IGF)-1 or lower levels of IGF binding protein (IGFBP)-3. However, there are no data testing strategies to lower levels of insulin or related hormones in colorectal cancer survivors. Two strategies that have strong scientific rationale to impact the insulin-related pathways are exercise intervention and metformin. This project will explore these strategies through a multi-site clinical trial.