Sociodemographic and clinical factors associated with low muscle mass and composition in people treated with (chemo)radiotherapy for lung cancer

This study examined (1) associations between sociodemographic and clinical variables with low muscle mass and radiodensity and their loss relative to treatment commencement in patients with lung cancer; and (2) the magnitude of change in muscle mass and association with treatment outcomes and survival. Prospective study in patients planned for curative (chemo)radiotherapy for lung cancer. Low skeletal muscle mass and radiodensity and muscle loss were determined from pre- and post-treatment computed tomography images. Sociodemographic, clinical, functional, nutritional, physical activity and alternate body composition were assessed pre-treatment. Logistic and linear regression and Fisher's exact tests were used to assess associations between variables and study outcomes. Cox proportional hazards models were fitted to examine associations with survival. Overall, 53 patients (62.3% male) with a mean age of 69 ± 9.3 years and 54.8% with stage III disease were included. Pre-treatment low calf circumference was associated with pre-treatment low muscle mass (p = 0.006). Higher comorbidity scores pre-treatment were associated with normal muscle radiodensity pre- and post-treatment (p = 0.015, p = 0.027, respectively). Pre-treatment low energy and protein intake were associated with low muscle radiodensity post-treatment. Muscle mass and radiodensity were not associated with survival or treatment outcomes. In patients with lung cancer, there is some evidence anthropometric measures of muscle mass are suggestive of low muscle mass pre-radiotherapy, while low energy intake pre-treatment may indicate low muscle radiodensity after treatment. However, these findings are limited by the small sample size and further prospective studies with larger samples are required.