151751-Najiba-Chargi

55 Diagnostics: measuring skeletal muscle mass of the musculus masseter INTRODUCTION Head and neck squamous cell carcinoma (HNSCC) is the seventhmost common type of cancer worldwide with 890.000 new cases and 450.000 deaths in 2018. It is commonly diagnosed in elderly patients in association with heavy alcohol and tobacco use. 1 Human papillomavirus (HPV) associated oropharyngeal cancer is found in younger patients and has a more favorable prognosis due to better responses to chemo- and radiotherapy and these patients have fewer comorbidities than patients with HPV-negative HNSCC. Approximately 30 to 40% of patients present with early-stage disease, which is defined as stage I or II, meaning at least 60% of patients present with advanced stage disease defined as stage III or IV. Advanced stage dis - ease is characterized by large tumors with local invasion, regional lymph node involvement and/or distant metastases. HNSCC at this stage is associated with a high risk of locoregional recurrence and distant metastasis resulting in a poor 5-year overall survival of less than 50%. There is a need for accurate prognostic factors to tailor treatment for HNSCC patients, and sarcopenia is emerging as a novel candidate in HNSCC. 2–4 Sarcopenia is defined as the loss of skeletal musclemass (SMM) andmuscle function 5 , although measurements of only SMM are often used in literature. Sarcopenia was first thought to be a physiological state in the elderly, however scientific research has changed the perception of the condition and uncovered a myriad of causes. Sarcopenia can be the result of cancer cachexia, a disruption in energy and protein balance caused by reduced food intake and hy- permetabolism. Cancer cachexia can be divided in three clinical stages: precachexia, cachexia and refractory cachexia. Progression between stages is dependent on factors such as cancer type and stage, decreased food intake and therapy resistant disease. 6,7 Patients with HNSCC are at an increased risk for cancer related cachexia and sarcopenia. Partly this is due to dysphagia caused by tumor localization or its treatment and side effects thereof. Moreover, patients with HNSCC might present with underlying malnutrition caused by poor diet, tobacco use or alcohol abuse. 8,9 Sarcopenia, and particularly low SMM, has been associated with adverse treatment outcome in patients with cancer. Sarcopenic cancer patients treated with surgery are at risk for com - plications and decreased survival. 10 In HNSCC, low SMM has been associated with and in - creased risk of surgical complications and cisplatin dose-limiting toxicity and with decreased survival. 11–13 Low SMM can be considered as an emerging biomarker for the clinical setting in HNSCC patients. 14 While the gold standard for total SMM assessment is full body imaging, earlier research has shown that the muscle cross-sectional area (CSA) measured on a single abdominal cross-sec - tional slice at the level of the third lumbar vertebra (L3) on computed tomography (CT) imag - ing can provide accurate estimates of patient’s total SMM. 15 Unfortunately, patients treated for head and neck cancers do not usually have imaging performed at this level. Therefore, a 4