Resting energy expenditure in children with cancer undergoing chemotherapy using indirect calorimetry: A longitudinal study

Background and aims Malnutrition is common among children with cancer and is related to treatment-related toxicity, mortality and lower quality of life. So far, it remains unknown whether changes in resting energy expenditure (REE) contribute to the development of malnutrition. Here, we explored alterations in measured REE (mREE) in children undergoing chemotherapy during the first nine months of treatment, and whether mREE per kilogram fat free mass (mREE/kgFFM) differs across patients with different body composition profiles. Finally, we compared mREE to predicted REE (pREE) by the Schofield equation to determine whether the Schofield equation adequately reflects REE in children with cancer. Methods Seventy-six children with cancer were included in this longitudinal study. mREE was measured using indirect calorimetry at 6–11 weeks (T0), 12–23 weeks (T1) and 24–36 weeks (T2) after diagnosis. Differences in mREE/kgFFM between time points were analyzed using the Wilcoxon signed-rank test. Linear regression models were conducted to explore the association between age, sex or tumor type and mREE/kgFFM. To examine whether the distribution of mREE/kgFFM varied across body composition categories, the Kruskal–Wallis test was employed. Differences between mREE and pREE were analyzed using the Wilcoxon signed-rank test. Agreement between mREE and pREE was assessed with Bland–Altman plots. Results At T0, T1 and T2, median (Q1-Q3) mREE (kcal/kgFFM/day) was 35.8 (26.8–44.9), 40.3 (32.2–48.4) and 46.0 (38.0–54.0), respectively. Across the three time points, there were no significant differences in mREE/kgFFM. Age (β = −2.07, 95% CI [-2.52,-1.62]), but not sex or tumor type, was inversely associated with mREE/kgFFM. There was no significant difference in distribution of mREE/kgFFM across body composition categories. mREE was significantly different from pREE at T0 and T1, but not at T2. Mean differences (kcal/day) with corresponding 95% limits of agreement for T0, T1 and T2 were −55 kcal/day (-321-212), −72 kcal/day (-410- 267) and −52 kcal/day (-452-348), respectively. Conclusion In this study, REE did not change during treatment in children with cancer. Furthermore, mREE/kgFFM was not associated with tumor type and did not differ significantly across patients with varying body composition profiles. Finally, the Schofield equation should be used with caution in this population, as individual-level differences compared to mREE may be clinically relevant.