Pretreatment subcutaneous adipose tissue predicts the outcomes of patients with head and neck cancer receiving definitive radiation and chemoradiation in Taiwan

We aimed to determine whether body composition assessment before treatment can predict outcomes in patients with head and neck cancer (HNC). All 881 patients with locoregional head and neck cancer treated with curative intent radiotherapy (RT) between 2005 and 2012 were retrospectively investigated. Body composition was analyzed via pre‐RT planning computed tomography (CT) images. Subcutaneous adipose tissue (SAT) and skeletal muscle (SM) indices were measured cross‐sectionally at the level of the third thoracic vertebra. Overall survival (OS), locoregional control (LRC), and distant metastasis‐free survival (MFS) were analyzed by body composition index and body mass index (BMI). Survivors were followed up for a median of 4.68 years. The SAT indices in female patients were significantly higher than those in males (P < 0.001). The median SAT and muscle indices were 18.6 and 34.3 cm(2)/m(2) for women and 6.19 and 51.74 cm(2)/m(2) for men, respectively. The 5‐ and 10‐year MFS, LRC, and OS rates were 83% and 82.1%, 73.4% and 71.4%, and 66.4 and 57.6%, respectively. Higher pretreatment SAT index was associated with MFS (hazard ratio [HR]: 0.65; P = 0.015), LRC (HR: 0.758; P = 0.047), and OS (HR: 0.604; P < 0.001). Higher pretreatment BMI was associated with MFS (HR: 0.642; P = 0.031) and OS (HR: 0.615; P < 0.001). The pretreatment SM index had no significant effect on MFS, LRC, and OS. Multivariate analysis revealed that T‐stage, N‐stage, lesion sites, age, and RT treatment days are independent factors associated with OS; T‐stage, N‐stage, and lesion sites are independent factors associated with MFS; and N‐stage, smoking history, and betel quid chewing history are independent factors associated with LRC. A higher CT‐assessed SAT index predicts superior MSF, LCR, and OS in patients with curative HNC, whereas SM does not predict survival or locoregional control.