Purpose: To systematically review and summarize evidence relevant to obesity and breast cancer clinical outcome, potential hormonal mediating mechanisms, and the current status of weight loss interventions for chronic disease management.
Methods: A comprehensive, formal literature review was conducted to identify 5,687 citations with key information from 159 references summarized in text and tables. This process included a search for all breast cancer studies exploring associations among survival or recurrence and obesity at diagnosis or weight gain after diagnosis using prospective criteria.
Results: On the basis of observational studies, women with breast cancer who are overweight or gain weight after diagnosis are found to be at greater risk for breast cancer recurrence and death compared with lighter women. Obesity is also associated with hormonal profiles likely to stimulate breast cancer growth. Recently, use of weight loss algorithms proven successful in other clinical settings that incorporate dietary therapy, physical activity, and ongoing behavior therapy have been endorsed by the National Institutes of Health and other health agencies.
Conclusion: Although definitive weight loss intervention trials in breast cancer patients remain to be conducted, the current evidence relating increased body weight to adverse breast cancer outcome and the documented favorable effects of weight loss on clinical outcome in other comorbid conditions support consideration of programs for weight loss in breast cancer patients. Recommendations for the clinical care of overweight or obese breast cancer patients are offered.