Retrospective cohort study of association of body composition metrics with overall survival in head and neck cancer radiotherapy

Advancing the prognostication of patients with head and neck cancer (HNC) who are undergoing radiotherapy (RT) may guide clinicians to better individualize support throughout oncologic treatment. A retrospective cohort study at University of California Los Angeles investigated the association of body composition metrics with overall survival (OS) among HNC patients undergoing RT between 2014 and 2024. Cohort filtering was applied to exclude palliative, abbreviated, or nonstandard treatment regimens. The primary clinical cohort comprised 1187 patients (median age 64.0 years; range 5.0-100.0; 27.2% females), with an imaging subcohort of 659 patients. While elevated body mass index categories were associated with OS (overweight versus normal weight HR 0.70; 95% CI 0.56-0.89; obesity versus normal weight 0.67; 0.50-0.89), a volumetric analysis revealed that this expansion was disproportionally associated with subcutaneous adiposity gain rather than muscle growth. In the imaging subcohort, elevated skeletal muscle was associated with improved OS (per each 1-SD increase HR 0.67; p=0.001), whereas elevated intermuscular adiposity was independently associated with worse OS (per each 1-SD increase HR 1.28; p=0.02). The authors conclude that these results suggest that higher body mass index was associated with improved overall survival. Automated volumetric CT phenotyping revealed that higher skeletal muscle and lower intermuscular adiposity were also associated with improved survival outcomes.