Resting energy expenditure, body composition, and metabolic alterations in breast cancer survivors vs. healthy controls: A cross-sectional study

AbstractPurpose:This study aimed to investigate the difference in absolute and relative measured resting energy expenditure (mREE) and body composition (body weight, fat mass (FM), fat free mass (FFM)) between breast cancer survivors (BCs) and controls. Correlations with body composition were analyzed. We examined if survival year, the metabolic state, or being metabolically dysfunctional were confounding factors.Methods:A cross-sectional analysis was conducted on 32 BCs ≤5years post treatment and 36 healthy controls. Indirect calorimetry measured absolute mREE. Body composition was determined by BOD POD. Relative mREE was calculated (absolute mREE/FFM). The Harris-Benedict equation was used to predict REE and determine the metabolic state (mREE/pREE). The database of the multidisciplinary breast clinic of the University Hospital of Antwerp was consulted for survival year and metabolic dysfunctions.Results:BCs have similar absolute mREE and greater relative mREE compared to controls with similar body composition. Absolute mREE and body composition between BCs differed; relative mREE was similar. FFM correlated significantly with absolute and relative mREE in BCs. A significant interaction term was found between survival year and FM for absolute mREE. The metabolic state was a significant contributor to absolute and relative mREE.Conclusion:BCs have similar or higher mREE. Differences in body composition between BCs are suggested to cause inter-individual variations in absolute mREE. We hypothesize that increased energy requirements are caused by metabolic stress related to cancer/treatment. Accurate measurement of REE and body composition is advised when adapting nutritional strategies, especially in patients at risk for developing metabolic dysfunctions.