Skeletal Muscle Mass in Major Head and Neck Cancer Surgery

his thesis focuses on the predictive and prognostic value of low skeletal muscle mass (SMM) in patients that have undergone major head and neck cancer (HNC) surgery. The results of these researches could help to improve pre-surgical risk-stratification, which can be used to select the optimal (surgical) treatment. In Chapter 2 the predictive value of low SMM was studied in 78 oral cavity cancer patients who underwent mandibular reconstruction with a free fibula flap at the University Medical Center Utrecht. Low SMM was significantly associated with an increased risk of flaprelated (HR 4.3) and severe surgical complications (Clavien-Dindo grade III-IV) (HR 4.0). Low SMM was also prognostic for decreased overall survival (OS) (HR 2.4). Previous studies investigated the predictive value of several patient 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 SMM in these patients. Similar findings are presented in Chapter 3, where a bigger cohort of patients underwent soft tissue reconstruction with a forearm free flap after oral cavity cancer ablative surgery. The results corroborated our first study, where low SMM was a predictive factor for postoperative complications. In this study, low SMM was associated with an increased risk of free flap associated complications (OR 2.14) and it was also associated with severe complications (Clavien-Dindo grade III-IV) (OR 1.46). In Chapter 4 we found that contrary to the more extensive surgery with a higher risk of complications (chapter 2 and 3), low SMM was not predictive for increased postoperative complications in clinically T1-2 oral cavity cancer patients undergoing selective neck dissection (OR 1.28). In Chapter 5 our data on the predictive value of the impact of elevated systemic inflammation on postoperative morbidity in oral cavity cancer patients undergoing microvascular forearm free flap reconstruction demonstrated that although increased neutrophil-leukocyte-ratio showed a trend toward increased complications; it was low SMM that was significant as a predictor of any postoperative complications (OR 4.78), as it was or surgical as well as medical complications . in Chapter 6 the systematic review and meta-analysis presents a search strategy resulting in 6 studies that analyze a total of 1082 patients who underwent free flap surgery for head and neck cancer. The prevalence of low SMM between studies ranged from 24.6% to 61.5%. The meta-analysis showed an odds ratio for complications after surgery of 2.42. Therefore SMM is an independent risk factor for postoperative complications in head and neck cancer reconstructive surgery patients. This is an argument for implementing screening for low skeletal muscle in preoperative management to optimize surgical decision making in patients where major ablative head and neck defects are expected.