Impact of Diet Modifications on Body Weight, Body Composition, Treatment Outcomes, and Quality of Life During Primary Treatment for Breast Cancer: A Systematic Review

Abstract Context Breast cancer is a significant public health challenge, with 290 000 new cases annually and significant healthcare costs. Treatment advancements have led to improvements in survival, but common adverse effects include weight gain, fatigue, nausea, and taste changes, decreasing quality of life. Objective This review aims to assess the impact of diet and lifestyle interventions during primary treatment for breast cancer and their effects on body weight, body composition, treatment-related adverse outcomes, and patient-reported quality of life. Data Sources and Data Extraction A search of PubMed, CINAHL, and EMBASE conducted through May 10, 2023, identified 31 publications describing 27 interventions including diet or diet plus exercise. The Cochrane Risk of Bias tool assessed the quality of publications. Data Analysis The findings suggest that whole foods, aerobic and strength-training exercises, and intermittent fasting during treatment may improve body weight and composition, treatment-related outcomes, and quality of life. Limitations include variation in study duration, small sample sizes, and limited sociodemographic data. Conclusion Improvements seen with increased diet quality and reduced caloric intake, with or without exercise, challenge current standard-of-care recommendations during treatment for breast cancer. While there is a need for additional research, healthcare teams can confidently promote healthy diets and exercise during primary treatment for breast cancer to manage weight and improve treatment-related side effects and quality of life. Systematic Review Registration PROSPERO registration no. 42023425613.