Effect of healthy diet and exercise on chemotherapy completion rate in women with breast cancer: The Lifestyle, Exercise and Nutrition Early after Diagnosis (LEANer) study: Study protocol for a randomized clinical trial

Background: The World Cancer Research Fund and the American Cancer Society provide nutrition and physical activity guidelines for cancer survivors. Many women with breast cancer do not follow these guidelines and delay efforts toward following them until active treatment is complete. However, adoption of these recommended lifestyle behaviors soon after diagnosis may prevent adverse treatment-related side effects and may improve adherence to treatment, resulting in improved breast cancer prognosis. The Lifestyle, Exercise, and Nutrition Early after Diagnosis (LEANer) study is testing the effect of a nutrition and physical activity intervention on chemotherapy completion rates. Methods: 172 women with stage I-III breast cancer undergoing chemotherapy will be randomized 1:1 to a yearlong, 16 session, nutrition and exercise intervention or usual care control group. The intervention is delivered by registered dietitians specializing in oncology nutrition and exercise training. The intervention includes goal setting to meet nutrition and physical activity guidelines for cancer survivors. After each chemotherapy session, date and dose of each drug administered, and reason for dose-adjustments and/or dose-delays are abstracted from the electronic medical record or obtained from the treating oncologist. Chemotherapy completion rate is assessed as the average relative dose-intensity (RDI) for the originally planned regimen based on standard formulas. Secondary endpoints of endocrine therapy adherence, treatment-related side effects, and changes in inflammatory and metabolic biomarkers, body composition, and patient reported outcomes are assessed at four timepoints. Discussion: If successful, this study has the potential to make healthy lifestyle interventions a standard component of breast cancer treatment.