151751-Najiba-Chargi

385 The elderly head and neck cancer patient: sarcopenia and frailty MUSCLE FUNCTION Overall muscle function is strongly related to handgrip strength. 18 Handgrip strength was measured using a Jamar hydraulic handheld dynamometer according to the recommendations of the American society of hand therapists (ASHT) and expressed in kilograms (kg). Patients were asked to squeezemaximally with each hand. The average score of the left and right hands was used for analysis. Patients had low handgrip strength if the handgrip strength was below twenty-seven kg (men) or below sixteen kg (women). 13 SKELETAL MUSCLE MASS Skeletal muscle mass was measured in all patients at the level of the third cervical vertebrae (C3) as cross-sectional muscle area (CSMA) on CT or MRI imaging before initiating treatment. The axial slice of the imaging which showed both transverse processes and the entire vertebral arc was selected for the segmentation of muscle tissue (Figure 1). For CT imaging, muscle area was defined as the pixel area between the radiodensity range of − 29 and + 150 Hounsfield units (HU), which is specific for muscle tissue. 19 For MRI, muscle area was manually segment - ed, and fatty tissue was manually excluded. Segmentation of muscle tissue was manually performed using the commercially available software package SliceOmatic (version 5.0, To - movision, Canada). The first author (CM) performed skeletal muscle mass measurements in all 150 patients. The cross-sectional muscle area at the level of C3 was converted to CSMA at the level of L3 using a formula published by Swartz et al. 20 The lumbar skeletal muscle index (SMI) was calcu - lated by correcting skeletal muscle mass at the level of L3 for squared height. Patients had a low SMI if this value was ≤43.2 cm 2 /m 2 ; this cut-off value was established in a separate cohort of patients with HNC. 14 Figure 1. Example of segmentation of skeletal muscle tissue at the level of the third cervical vertebra (C3) Figure shows two identical axial computed tomography (CT) slides at the level of C3; left shows themuscle tissue unsegmented, right shows both sternocleidomastoid and paravertebral muscles segmented in red. 19