151751-Najiba-Chargi

17 Introduction Figure 2. Skeletal muscle mass segmentation (red) at the level of L3 for three different patients with different body mass index (BMI) but same skeletal muscle mass. 27 Abdominal CT is routinely performed during diagnostic work-up and follow-up of many cancer patients, and thus imaging is routinely available for analysis without any extra burden for the patient or healthcare-related costs. In 2008, Prado et al. showed that there is a linear rela - tionship between a person’s height and the skeletal muscle area at the level of L3. 40 Therefore the skeletal muscle area at the level of L3 is adjusted for squared height, to calculate the skeletal muscle index (SMI; cm 2 /m 2 ), as a estimation of a person’s total skeletal muscle mass in proportion to stature. 40 Prado et al were the first to investigate the relationship between low skeletal muscle mass (low skeletal muscle mass index) and adverse outcomes in patients with cancer. 40,41 Since 2008, various studies have shown that low skeletal muscle mass is asso- ciated with increased rates of postoperative complications, chemotherapy-related toxicity, prolonged hospital stay, increased healthcare related costs, and decreased overall and dis- ease-specific survival rates in patients with colon cancer, breast cancer, lung cancer, bladder cancer, pancreatic cancer and hematological malignancies, amongst others. 42–50 Abdominal CT imaging is not routinely performed in head and neck cancer patients and is often only available in patients with locally advanced disease. In 2016, Swartz et al. published a novel assessment method for skeletal muscle mass using a single CT slice at the level of the third cervical verte- bra (C3), which is featured on regular head and neck CT imaging. 51 Figure 3 shows an example of skeletal muscle mass segmentation on the level of C3 in which both sternocleidomastoid muscles and the paravertebral muscles are segmented. 1