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

Abstract

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.

Feasibility of eccentric overloading and neuromuscular electrical stimulation to improve muscle strength and muscle mass after treatment for head and neck cancer

“…Recruitment was initiated in October 2017 and ended in February 2019. The recruitment strategy was identical to that used in our previous work, where patients with HNC attending a 2-hour education session prior to radiation therapy received a short presentation regarding the study [13]. People who indicated that they would be interested in receiving more information about the study were contacted and invited to participate approximately 4 weeks following their final dose of radiation.…”

“…Participants (see Table 1) attended the Human Performance Laboratory (Faculty of kinesiology, University of Calgary, AB, Canada) to participate in a baseline assessment protocol that was identical to the procedures used in our previous work [13]. The baseline assessment took place 57 ± 30 days after the final radiation dose.…”

“…Following the intervention, the assessments were repeated a minimum of 72 hours (and maximum 5 days) after the final exercise session to allow for sufficient recovery and to ensure possible muscle damage did not affect the results [30]. A full explanation of the methods used for testing procedures and the experimental setup has been previously described elsewhere [13]. questionnaire.…”

“…Vastus lateralis and rectus femoris muscle CSA were evaluated using B-mode ultrasonography (GE Medical Systems LOGIQ E9, Wauwatosa, WI), which is a reliable and validated method for assessing quadriceps atrophy and hypertrophy [31]. Neuromuscular function was determined using isometric dynamometry and femoral nerve electrical stimulation [13]. Performance fatigability was evaluated by an incremental cycling test performed on a cycle ergometer [32] that included instantaneous and intermittent maximal isometric voluntary contractions (MIVCs) and electrical nerve stimulation for the assessment of volitional and non-volitional aspects of a reduction in MIVC force, respectively.…”

“…Intervention modalities have been limited to conventional strength training, where dynamic voluntary muscle contractions are performed against external loads [12], including concentric and eccentric muscle actions. However, dietary intake and weight loss can continue to be problematic after HNC treatment completion, and this may contribute to a reduced exercise capacity [13]. Therefore, the effectiveness of conventional strength training programs may be restricted, and there is scope and need to investigate optimizing training modalities that maximizes the stimulus while limiting the associated energy expenditure.…”