Findlay M, et al. J Hum Nutr Diet 2020.
BACKGROUND: Computed tomography (CT) is the gold standard of body composition analysis at the tissue-organ level. The present study aimed to determine the impact of CT-defined sarcopenia and myosteatosis on outcomes, including overall survival, unplanned hospital admissions and related costs, in patients who had completed treatment of curative intent for head and neck cancer (HNC).
METHODS: Retrospective observational study of patients undergoing radiotherapy of curative intent ± other treatment modalities for HNC. Tissue density data derived at the third lumbar vertebra (L3) were evaluated with sarcopenia defined per sex-specific published threshold values for skeletal muscle index, stratified by body mass index and mean skeletal muscle attenuation in HU (Hounsfield units).
RESULTS: Pre- or post-treatment images were available for 79/98 patients (80.6%) and 61/98 patients (62.2%), respectively. Sarcopenia was present in 42/79 patients pre-treatment and 36/61 patients post-treatment, whereas myosteatosis was present in 63/79 patients pre-treatment and 48/61 patients post-treatment. In patients with pre- and post-treatment images (n = 60), the median (range) percentage weight change was -8.5% (-29.9 to +11.7). On multivariable analysis, a post-treatment sarcopenia hazard ratio of 3.87 (95% confidence interval = 1.22-12.24, P = 0.021) and a pre-treatment myosteatosis hazard ratio of 8.86 (95% confidence interval = 1.12-69.88, P = 0.038) were independent predictors of reduced overall survival. There was no difference in radiotherapy or chemotherapy treatment completion based on pre-treatment sarcopenia status. The mean (SD) difference unplanned hospital admission cost was $15 846 ($17 707) for patients without sarcopenia versus $47 945 ($82 688) for patients with sarcopenia at any time point (P = 0.077).
CONCLUSIONS: As CT-defined sarcopenia and myosteatosis hold clinically meaningful prognostic value, muscle status evaluation is recommended in routine clinical practice.