Abstract
BACKGROUND: Obesity is characterized by chronic mild inflammation and may influence the risk and progression of cancer. PURPOSE: The current study is an exploratory analysis of the effect of a weight loss intervention that emphasized increased physical activity on inflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], interleukin-8 [IL-8], and vascular endothelial growth factor [VEGF]) at the end of the 16-week intervention period in overweight breast cancer survivors. METHODS: Study participants averaged 56 years of age (N=68). Intervention participants (n=44 vs. 24 controls) participated in a cognitive behavioral therapy-based weight management program as part of an exploratory randomized trial. The intervention incorporated strategies to promote increased physical activity and diet modification. Baseline and 16-week data included height, weight, body composition, physical activity level, and biomarkers IL-6, IL-8, TNF-α, and VEGF. RESULTS: Weight loss was significantly greater in the intervention group than controls (-5.7 [3.5] vs. 0.2 [4.1] kg, P<0.001). Paired t tests noted favorable changes in physical activity level (P<0.001 intervention, P=0.70 control), marginally lower IL-6 levels (P=0.06 intervention, P=0.25 control) at 16 weeks for participants in the intervention group, and lower TNF-α levels for participants in the intervention (P<0.05) and control groups (P<0.001). Increased physical activity was associated with favorable changes in IL-6 for participants in the intervention group (R(2) =0.18; P<0.03). CONCLUSION: Favorable changes in cytokine levels were observed in association with weight loss in this exploratory study with overweight breast cancer survivors.