In a study published in JAMA Network, healthy lifestyle behaviors, as defined by the American Cancer Society and American Institute of Cancer Research, were associated with a 37% reduced hazard of breast cancer recurrence and a 58% reduced hazard of mortality.

Partial and full adherence to the physical activity and smoking recommendations and full adherence to fruit and vegetable and sugar-sweetened beverage recommendations were associated with reduced disease recurrence; no statistically significant associations were observed for BMI, red and processed meats, or alcohol consumption (Figure 3A). Additionally, full adherence to PA, smoking, fruit and vegetable, and sugar-sweetened beverage recommendations and partial and full adherence to red and processed meat recommendation were associated with significant reductions in mortality.

In this prospective cohort study of adherence to cancer prevention guidelines before, during, and after treatment for high-risk BC, strongest adherence to cancer prevention lifestyle recommendations was associated with a 58% reduction in mortality and a 37% reduction in disease recurrence. Associations were not modified by educational attainment, self-identified race or ethnicity, or menopause status, and significant reductions in recurrence and mortality were consistently observed even among patients diagnosed with more aggressive BC subtypes.

Although the putative influences of diet, exercise, and smoking on the cellular processes underpinning the progression of BC have been extensively reviewed,^1,2,19 to our knowledge, this is the first report showing that lifestyles before, during, and after chemotherapy were associated with improved outcomes in patients with high-risk BC. Although no prior reports have described associations of an aggregated LIS from multiple time points with high-risk BC outcomes, our findings coincide with previous reports showing that healthier lifestyle scores are associated with better survival in patients diagnosed with a variety of tumors.^19,32–40