Randomized trial of weight loss in primary breast cancer: Impact on body composition, circulating biomarkers and tumor characteristics

NK cell expression was positively associated with weight loss; CC-ARG increased with physical activity. Increased tumor (nuclear) TNFα and IL-1β, CX3CL1 and CXCL1 gene expression was observed in the WLI. Tumor Ki67 did not differ between arms. Feasibility benchmarks included 80% accrual, 100% retention, no adverse effects and excellent adherence. Short-term weight loss interventions are feasible; however, mixed effects on tumor biology suggest unclear benefit to presurgical caloric restriction, but possible benefits of physical activity.