title: Lean body mass and muscle function in head and neck cancer patients and healthy individuals--results from the DAHANCA 25 study.
abstract: BACKGROUND
  Loss of lean body mass is common following radiotherapy in patients with head and neck squamous cell carcinoma (HNSCC) and may reduce maximal muscle strength and functional performance. However, the associations between lean body mass, muscle strength and functional performance are unclear and no studies in HNSCC patients have compared the levels of these variables to the levels seen in healthy individuals.
  
  
  OBJECTIVE
  The purpose of the present study was to investigate the associations between lean body mass, maximal muscle strength and functional performance in HNSCC patients and to compare the levels of these variables after radiotherapy and after progressive resistance training with the levels in healthy individuals.
  
  
  METHODS
  Lean body mass (dual energy X-ray absorptiometry), maximal muscle strength (isokinetic dynamometry) and functional performance (10 m max gait speed, 30 s chair rise, 30 s arm curl, stair climb) from HNSCC patients from the DAHANCA 25 trials and data from 24 healthy individuals were included.
  
  
  RESULTS
  Lean body mass and maximal muscle strength were significantly associated according to the gender and age-adjusted linear regression model (p < 0.0001). In addition, maximal muscle strength were associated with 30 s arm curl performance, 10 m max gait speed and 30 s chair rise (p < 0.0001). Multiple regression analyses showed that HNSCC patients expressed significant lower levels of the investigated variables after radiotherapy than healthy individuals (p < 0.0001), and that all differences were evened out after training.
  
  
  CONCLUSIONS
  Significant associations were found between lean body mass, maximal muscle strength and functional performance in HNSCC patients. Patients expressed lower levels of these variables compared with healthy individuals, suggesting that lean body mass is a clinically relevant health factor in HNSCC patients.
authors: Department of Experimental Clinical Oncology, Aarhus University Hospital , Aarhus , Denmark.
authors: Simon
authors: S
authors: Lønbro
authors: Ulrik
authors: U
authors: Dalgas
authors: Hanne
authors: H
authors: Primdahl
authors: Jørgen
authors: J
authors: Johansen
authors: Jakob Lindberg
authors: JL
authors: Nielsen
authors: Jens
authors: J
authors: Overgaard
authors: Kristian
authors: K
authors: Overgaard
mesh_terms: D000328:Adult; D000368:Aged; D001823:Body Composition; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000503:physiopathology* / Q000532:radiotherapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D011379:Prognosis; D011597:Psychomotor Performance / Q000502:physiology*; D011879:Radiotherapy Dosage; D055070:Resistance Training; D013851:Thinness