Agreement between muscle mass assessments by computed tomography and calf circumference in patients with cancer: A cross-sectional study

Cancer influences body composition, including a loss of muscle mass (MM), associated with worse outcomes. The study aimed to evaluate the agreement between MM estimated by calf circumference (CC) and computed tomography (CT) image as a reference method. A cross-sectional study including patients (>20 years) diagnosed with cancer attending a reference center of oncology. Spearman's correlation was performed to verify the correlation between CC and MM by CT, including skeletal muscle area - SMA and skeletal muscle index - SMI. ROC curves, Kappa coefficient, sensitivity, specificity, positive and negative predictive values were obtained. The study included 219 patients, age 62.9 ± 13.1 years (mean ± standard deviation). Low CC was observed in 43.8% of the patients, and 29.2% had low SMI. CC positively correlated with SMA (rho = 0.333) and SMI (rho = 0.329), and fair agreements (K = 0.268) were observed between CC and SMI, with higher and significant values for males (K = 0.332) and patients below 60 years (K = 0.419). The area under the curve (AUC) for low CC to identifying low SMI was equal to 0.685 (CI 95% 0.606–0.765). Low CC presented fair agreement to identify low SMI in the sample; however, the negative predictive value was almost 80% for all analyses. Low CC is not a surrogate for low SMI in patients with cancer, but it could be an alternative, non-invasive, easy-to-perform method to pre-screen patients with cancer with adequate SMI.