Neuromuscular function and fatigability in people diagnosed with head and neck cancer before versus after treatment

Purpose: Treatment for head and neck cancer is associated with multiple side-effects, including loss of body mass, impaired physical function, and reduced health-related quality of life. This study aimed to investigate the impact of treatment (radiation therapy ± concurrent chemotherapy) on (i) muscle strength, muscle cross-sectional area and patient-reported outcomes, and (ii) central and peripheral alterations during a whole-body exercise task.Methods: Ten people with head and neck cancer (4 female; 50±9 years) completed a lab visit before and after (56±30 days) completion of treatment. Participants performed a neuromuscular assessment (involving maximal isometric voluntary contractions in the knee extensors and electrical stimulation of the femoral nerve) before and during intermittent cycling to volitional exhaustion. Anthropometrics and patient-reported outcomes were also assessed.Results: From before to after treatment, maximal isometric muscle strength was reduced (P=0.002, d=0.73), as was potentiated twitch force (P<0.001, d=0.62), and muscle cross-sectional area (e.g. vastus lateralis: P=0.010, d=0.64). Exercise time was reduced (P = 0.008, d = 0.62) and peripheral processes contributed to a reduction in maximal force due to cycling. After treatment, the severity of self-reported fatigue increased (P=0.041, r=-0.65) and health-related quality of life decreased (P=0.012, r=-0.79).Conclusion: Neuromuscular function was impaired in patients with head and neck cancer after treatment. Whole-body exercise tolerance was reduced and resulted in predominantly peripheral, rather than central, disturbances to the neuromuscular system. Future research should evaluate strength training after treatment for head and neck cancer, with the overall aim of reducing fatigue and improving health-related quality of life.