Change of skeletal muscle mass and associated factors during radiotherapy and chemoradiotherapy in patients with head and neck squamous cell carcinoma

The aim is to investigate whether lumbar skeletal muscle index (LSMI) decreases during treatment of head and neck squamous cell carcinoma (HNSCC) patients, and which pre-treatment variables are associated with change. The LSMI before and during treatment was assessed using MRI scans of HNSCC patients treated with radiotherapy (RT) or chemoradiotherapy (CRT). Mixed models assessed LSMI change and pre-treatment covariates (i.e. age, BMI, tumor characteristics and treatment type). In 63 patients the LSMI decreased from 40.56 cm 2 /m 2 to 39.96 cm 2 /m 2 ( p trend = 0.008) on average. The LSMI of CRT patients decreased more than the LSMI of RT patients, but this was not significant (40.85–39.63 cm 2 /m 2 vs. 40.37 to 40.19 cm 2 /m 2 ; p-interaction = 0.052). No effects of pre-treatment covariates on the LSMI trend over time were observed. LSMI decreased during treatment in HNSCC patients, which was not related to pre-treatment variables, but seemed slightly larger for CRT patients than RT patients. • Patients with head and neck cancer lose skeletal muscle mass during radiotherapy. • Skeletal muscle mass decreases more during chemoradiotherapy than radiotherapy. • Decrease of skeletal muscle mass is difficult to predict pretreatment.