Abstract
Changes in body composition and muscle dysfunction are common in metastatic breast cancer (MBC). Ultrasound imaging (US) offers reliable information about muscle and fat tissue architecture (thickness) and quality (echo-intensity). This study aimed to analyze the responsiveness of thickness and echo-intensity and its possible relationship with functional and patient reported-outcomes (PRO) in MBC patients after an exercise intervention. A prospective study was conducted in 2019. A 12-week exercise program was performed, including aerobic exercise and strength training. Measurements were made at baseline and after intervention. Thickness and echo-intensity were obtained from the quadriceps and biceps brachii and brachialis (BB). Mean differences were calculated using the T-Student parametric test for dependent samples of the differences in the means before and after the intervention (p = 0.05; 95% CI). Data from 13 MBC patients showed that some US muscle variables had significant differences after intervention. Best correlations were found between the quality of life questionnaire (QLQ-BR23) PRO and variables from BB muscle thickness in contraction (r = 0.61, p < 0.01), and Non-contraction (r = 0.55, p < 0.01). BB Muscle Non-contraction Thickness also explained 70% of QLQ-BR23 variance. In conclusion, muscle architecture biomarkers showed great responsiveness and are correlated with PRO after an exercise intervention in MBC patients.