151751-Najiba-Chargi

424 CHAPTER 21 cut-off values were calculated. For male patients with a BMI <25 kg/m 2 , a CSMI ≤6.8 cm 2 /m 2 was defined and with a BMI ≥25kg/m 2 a CSMI ≤8.5cm 2 /m 2 was defined for low skeletal muscle mass. For female patients with a BMI <25 kg/m 2 , a CSMI ≤5.3 cm 2 /m 2 was defined and with a BMI ≥25kg/m 2 a CSMI ≤6.4 cm 2 /m 2 was defined for low skeletal muscle mass. This study is the first to provide standardized cut-off values for low skeletal muscle mass at the level of C3 in patients with head and neck cancer. This informationmay aid in the uniformity of low skeletal muscle mass definition in research. Part II of this thesis presents the predictive and prognostic impact of skeletal muscle mass in surgically treated head and neck cancer patients. Chapter 6 presents the predictive value of low skeletal muscle mass in 78 oral cavity cancer patients who underwent mandibular reconstruction with a free fibula flap in University Medical Center Utrecht, the Netherlands. Low SMM was significantly associated with an increased risk for flap-related complications (HR 4.3, p<0.05) and for severe surgical complications (Clavien-Dindo grade III-IV) (HR 4.0, p<0.05). Low skeletal muscle mass was also prognostic for decreased overall survival (OS) (HR 2.4, p<0.05). Although several previous studies investigated the predictive value of several pa - tient-related and surgery-related factors for surgical complications in patients who underwent microvascular free flap reconstruction, this was the first study to examine the predictive and prognostic value of low skeletal muscle mass in these patients. Chapter 7 presents a cohort study performed in a larger cohort of patients undergoing microvascular free flap head and neck reconstruction. This large cohort study was performed at the department of Oral and Maxillofacial surgery in collaboration with dr. Parmar at the Queen Elizabeth hospital in Bir - mingham, United Kingdom. In total, 616 patients were included. Besides skeletal musclemass, the predictive and prognostic role of systemic inflammation was evaluated in these patients. Elevated neutrophil-to-lymphocyte ratio (NLR) was used as a marker for systemic inflam - mation. Non-flap and flap-related complications occurred in 39.3% and 12.3% of patients, respectively. Flap-failure rate was 4.7%. For oncological cases, elevated NLR showed to be a significant predictor for surgical complications in all types of flap-surgery (OR 1.5, p<0.05), low SMM in radial forearm flap surgery (OR 2.1, p<0.05) and elevated NLR combined with low SMM in fibula flap surgery (OR 5.2, p<0.05). Patients with solely elevated NLR were at significant risk for flap-related complications (OR 3.0), severe complications (Clavien-Dindo grade >IIIa) (OR 2.2, p<0.05) and when combined with low SMM for increased length of hospital stays (LOS) (+3.9 days, p<0.05). In early-stage HN squamous cell carcinoma (HNSCC), low SMM (HR 2.3, p<0.05) and combined elevated NLR with low SMM (HR 2.3, p<0.05) were prognostics for OS. Skeletal muscle mass and NLR are routinely available biomarkers, and this study provides evidence that these biomarkers may aid the clinician in the identification of patients at risk of a poor outcome. Chapter 8 presents another study in 224 surgically treated patients with oral cavity cancer to investigate the predictive impact of low skeletal muscle mass on periopera- tive complications. Low skeletal muscle mass was a significant predictor for the presence of perioperative complications (HR 1.5, p<0.01) and the number of perioperative complications (HR 1.5, p<0.01). Besides skeletal musclemass, arterial calcification is also assessed on routine diagnostic CT imaging and could be used as an additional image-based biomarker. Therefore,