Energy balance in cancer survivors at risk of weight gain: a review.

PURPOSE: The study of energy balance [i.e., energy intake (EI) and energy expenditure (EE)] is a powerful tool for understanding body weight regulation and may contribute to our understanding of rapid weight gain risk in certain cancer survivors post-diagnosis. The purpose of this review was to summarize studies that assessed longitudinal, prospective changes in components of energy balance from diagnosis/start of treatment to any duration of follow-up in cancer survivors with prior evidence of weight gain (breast, prostate, thyroid, gynecologic, testicular, and acute lymphoblastic leukemia)
RESULTS: The available literature suggests that energy balance components may be altered in cancer survivors who have a heightened risk of weight gain post-diagnosis. The evidence for EI was overall inconsistent. Conversely, decreases in resting and physical activity EE during the active phases of treatment (e.g., chemotherapy, hypothyroid state) were commonly noted, which then slowly rebounded towards baseline levels at the end of treatment and during follow-up assessments. Much of this evidence is based on data collected from breast cancer survivors, which highlights a paucity of data currently available on other cancer types.
CONCLUSIONS: While there is growing acknowledgement that weight management interventions in cancer survivors are needed, it is important to recognize that changes in both behavioral (EI, physical activity EE) and passive (resting EE, thermic effect of food) components of energy balance may occur post-diagnosis. This information can help to inform weight management interventions which often entail modifications in diet and/or physical activity.