Changes in body composition and muscle attenuation during taxane-based chemotherapy in patients with metastatic breast cancer

Body composition parameters including low muscle mass, muscle attenuation (which reflects muscle quality) and adipose tissue measurements have emerged as prognostic factors in cancer patients. However, knowledge regarding the possibility of excessive muscle loss during specific systemic therapies is unknown. We describe the changes in body composition and muscle attenuation (MA) during taxane- and anthracycline-based regimens and its association with overall survival (OS) in metastatic breast cancer patients. The lumbar skeletal muscle index (LSMI) was used as marker of muscle mass. LSMI, MA, subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and intramuscular adipose tissue (IMAT) were measured before and after first-line treatment with paclitaxel (n = 73) or 5-fluorouracil-doxorubicin-cyclophosphamide (FAC) (n = 25) using CT-images. Determinants of the change of LSMI and MA were analyzed using multiple linear regression. OS was assessed using Cox proportional hazard models. MA significantly decreased during paclitaxel treatment (- 0.9 HU, p = 0.03). LSMI (p = 0.40), SAT (p = 0.75), VAT (p = 0.84) and IMAT (p = 0.10) remained stable. No significant alterations in body composition parameters during FAC-treatment were observed. Previous (neo-)adjuvant chemotherapy contributed to larger loss of MA during the current treatment. Body composition changes during chemotherapy were not associated with OS. MA decreased during treatment with paclitaxel, while muscle mass was stable. Body composition changes are not associated with survival in the absence of progressive disease.