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

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.