151751-Najiba-Chargi

364 CHAPTER 18 by the combination of low SMM and low MF, and adverse outcomes. The aim of this study is to explore the relationship between sarcopenia and overall survival in elderly patients with head and neck cancer. MATERIALS AND METHODS PATIENTS AND STUDY DESIGN This study was designed as a single-center retrospective study. We reviewed elderly patients (≥70-year-old) with pathologically proven head and neck squamous cell carcinoma (HNSCC) who had a geriatric assessment during their diagnostic workup between April 2015 and Feb - ruary 2018. In our center elderly HNSCC patients are offered geriatric assessment, but patients may refuse. Histologic tumor types other than squamous cell carcinoma were excluded. The design of this retrospective study was approved by the Medical Ethical Research Committee of our center (approval ID 17-365/C). Factors with known or suspected relation with HNSCC treatment outcomes and with sarcopenia were collected: age, sex, body mass index (BMI), weight loss in the past six months, risk of malnutrition assessed with the malnutrition univer- sal screening tool (MUST), smoking status, alcohol use, comorbidity expressed as a Charlson Comorbidity Index (CCI) score, tumor type (primary, second primary or recurrence), tumor site, human papillomavirus (HPV) status (for oropharyngeal cancer), tumor-node-metastasis (TNM) stage, hematological and biochemical markers at diagnosis, including hemoglobin (Hb), leukocytes, C-reactive protein (CRP), creatinine and albumin, and treatment intention. DEFINITION OF SARCOPENIA Sarcopenia was defined as the combination of low SMM and lowMF, as determined by muscle strength or physical performance measurements. 1 SKELETAL MUSCLE MASS Skeletal musclemass was measured as muscle cross-sectional muscle area (SMA) on pre-treat - ment CT or MRI imaging of the head and neck area at the level of the third cervical vertebrae (C3). The axial slide of the imaging which showed both transverse processes and the entire vertebral arc was selected for segmentation of muscle tissue. 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. 18 For MRI, muscle area was manually segmented, and fatty tissue was manually excluded. Segmentation of muscle tissue was manually performed using the commercially available software package SliceOmatic (Tomovision, Canada). Cross-sectional muscle area at the level of C3 was converted to CSMA at the level of L3 using a previously published formula. 19 The lumbar skeletal muscle index (SMI) was calculated by correcting SMM at the level of L3 for height. Patients had a low SMI if this value was ≤43.2cm²/m²; this cutoff value was established in a separate cohort of head and neck cancer patients. 7