Association of sarcopenia and frailty in head-and-neck cancer by different imaging methods: a scoping review

Sarcopenia and frailty are emerging indicators of vulnerability in patients with head-and-neck cancer (HNC), yet their relationship and combined clinical relevance remain unclear. This scoping review aimed to map and synthesize the available evidence on the relationship, overlap, and combined clinical relevance of sarcopenia and frailty in patients with HNC, with particular focus on their associations with postoperative complications, treatment-related toxicity, survival, and patient vulnerability. Original studies published in English were included if they involved adult patients with HNC and assessed sarcopenia or muscle-related parameters in relation to frailty, geriatric assessment, or frailty-associated clinical outcomes. A scoping review was conducted from database inception to May 2026 using keywords related to HNC, sarcopenia, frailty, and imaging. The review followed PRISMA-ScR guidelines and included peer-reviewed, full-text original clinical studies. Twelve articles, including 2275 patients, published between 2019 and 2026 on sarcopenia and frailty in HNC were included for final review. Eight studies were retrospective. The sample size for the included studies ranged from 47 to 568 participants and mean or median age ranging from approximately 54–82 years. The prevalence of sarcopenia ranged from 14 to 87%, depending on definition, while frailty prevalence ranged from 15 to 68%. Sarcopenia was mostly defined based on low skeletal muscle mass, whereas frailty was assessed using heterogeneous tools, most frequently the 5-item Modified Frailty Index (5-mFI). Sarcopenia was consistently associated with postoperative complications, treatment-related toxicity, and reduced survival, while frailty showed less consistent association with outcomes. Studies examining both conditions indicated that frail patients were more likely to be sarcopenic. Frail patients with HNC are more likely to be sarcopenic and sarcopenia is consistently associated with adverse clinical outcomes including complications, treatment intolerance, and reduced survival. Imaging-based assessment of skeletal muscle mass may serve as a practical and objective biomarker for identifying vulnerable patients, although heterogeneity in definitions and measurement methods limits comparability across studies.