Background: Malnutrition, including sarcopenia, is prevalent in patients with head and neck cancer. The relationship between pre-treatment sarcopenia and adverse oncologic outcomes in this population is well described, although the impact of myosteatosis and post-treatment sarcopenia is less well characterised.
Methods: 125 patients with head and neck squamous cell carcinoma (HNSCC) and prophylactic gastrostomy undergoing curative-intent therapy containing radiotherapy (RT) were assessed for evidence of sarcopenia and myosteatosis, using cross-sectional FDG-PET/CT imaging at the level of L3 vertebra. Sarcopenia was defined as radiologically-assessed muscularity less than the fifth percentile according to gender. Myosteatosis was assessed through calculation of mean muscle attenuation. Assessments were completed at baseline (pre-treatment) and approximately three months post-treatment and associated with progression-free and overall survival (OS) at 12 months and five years post-treatment completion.
Results: 101 participants had a CT scan evaluable at one or two timepoints, of which 67 (66%) participants were sarcopenic on at least one timepoint. Increasing age was significantly associated with risk of sarcopenia (OR 1.09, 95% CI 1.04-1.15). 93%-97% patients had myosteatosis. Changes during treatment in body mass index (BMI) and weight were not different when comparing those with or without sarcopenia or myosteatosis pre-treatment. 5-year OS was significantly worse in those with post-treatment sarcopenia (HR 0.37, 95% CI 0.16-0.88) and those with post-treatment myosteatosis who were also sarcopenic (compared with not sarcopenic) (HR 0.33, 95% CI 0.13-0.83).
Conclusion: Rates of myosteatosis were high at both pre- and post-treatment timepoints. Body mass index and percentage weight loss does not differentiate those with or without sarcopenia or myosteatosis. Post-treatment sarcopenia was significantly associated with worse five-year overall survival, as was post-treatment sarcopenia in those who had myosteatosis. Post-treatment sarcopenia should be further evaluated as a novel independent risk factor for decreased long-term survival post-treatment containing RT for HNSCC. Myosteatosis, whilst being highly prevalent, does not seem to enrich survival prediction. Interventions targeting sarcopenia should be developed and tested.