Resting energy expenditure measured by indirect calorimetry in children with cancer: A systematic literature review

Background & aims Malnutrition can have serious effects on patient outcomes in children with cancer, including a decreased chance of survival, increased risk of treatment-related toxicities and an impaired quality of life. However, it remains insufficiently understood which factors are key determinants in the development of malnutrition in children with cancer. Given that resting energy expenditure (REE) is an important component of energy balance, we aimed to investigate whether REE is altered in children with cancer by reviewing and summarizing current literature comparing measured REE (mREE) in children with cancer to that of healthy peers or predicted REE (pREE). Methods A systematic search was conducted on Pubmed and Embase up to February 2025. All study designs were eligible for inclusion when they met the following criteria: (1) original studies including children (0–18 years) diagnosed with cancer, that (2) measured REE using indirect calorimetry, and (3) compared mREE with healthy controls or pREE derived from an established prediction equation. Results were reported in accordance with the PRISMA 2020 guidelines. Methodological quality of the included studies was assessed using an adapted version of the Critical Appraisal Skills Program Cohort Study Checklist. Results In total, 1673 unique publications were identified, of which 12 publications involving 212 patients met the inclusion criteria. The included studies were all of relative low quality with small samples sizes (range 7–40 patients). Considerable heterogeneity was observed across the studies with respect to age, diagnosis and treatment phase. Only 3 studies reported significant differences between mREE and healthy controls or pREE. One study performed in 13 children with newly diagnosed solid tumors reported a higher mREE compared to pREE derived from the Schofield equation, whereas another study performed in 40 children with various tumor types reported a lower mREE compared to pREE derived from the WHO equation. Additionally, 1 study performed in 20 children with leukemia during or after treatment reported a lower mREE compared to healthy controls. The remaining 9 studies included showed no significant difference between mREE and healthy controls or pREE. Conclusions There is inconclusive evidence to conclude that REE is altered in children with cancer. Larger longitudinal studies are needed to fully understand whether changes in REE contribute to the development of malnutrition in this population, and to explore differences across tumor types and treatment phases.