Body Composition Changes in Patients with Oropharyngeal Squamous Cell Carcinomas Treated With Radiotherapy

Patients with oropharyngeal squamous cell carcinomas (OPSCC) are often malnourished at diagnosis, can lose weight during treatment, and many require nutritional support. Different modes of weight loss exist, caused by fat and/or muscle loss, but current practice relies on monitoring weight alone. We aimed to determine whether routinely collected data could be used to model changes in body composition in greater detail.

Clinical and imaging data were retrospectively collected for 337 patients with OPSCC treated with radiotherapy (RT) at two tertiary cancer centres. Weekly weight measurements were used to monitor changes in weight; muscle mass was automatically measured from all on-treatment cone-beam computed tomography scans (CBCTs; n = 9432). Associations between weight change, muscle change, and overall survival were investigated in multivariable Cox regressions adjusting for known prognostic factors.

The rate of muscle loss was a significant prognostic factor (hazard ratio [HR]: 2.50 [1.03, 6.02], P = .03) in all analyses; greater muscle loss was associated with increased risk of all-cause mortality. After accounting for feeding tube use, rate of weight loss, muscle loss, and their interaction were found to provide independent prognostic information (P < .01). These results suggest that muscle and weight loss should be considered in tandem.

Monitoring muscle mass from routinely collected on-treatment CBCT imaging is feasible. In a multi-centre analysis of patients with human papillomavirus (HPV) positive OPSCC, we find that increased muscle loss during RT is associated with decreased survival. Comprehensive monitoring of body composition may benefit this population.