Exercise during preoperative therapy increases tumor vascularity in pancreatic tumor patients.

The efficacy of chemotherapy is reduced by dysfunctional tumor vasculature, which may limit chemotherapy delivery to tumors. Preclinical studies have shown that moderate aerobic exercise improves tumor vascular function and increases chemotherapy efficacy in mouse models, but the effect of exercise on human tumor vasculature has not yet been determined. Here, we demonstrate that exercise remodels the tumor vasculature, accelerates the regression, and delays the regrowth of pancreatic ductal adenocarcinoma in a patient-derived xenograft mouse model treated with gemcitabine. By evaluating pancreatic adenocarcinoma specimens from patients treated with preoperative chemotherapy or chemoradiation therapy, we also demonstrate for the first time that tumor vascular remodeling occurs in association with exercise in humans. Future studies will evaluate whether exercise-induced vascular remodeling improves gemcitabine or other chemotherapy efficacy in patients, as this study evaluated only changes in tumor vascular structure.