151751-Najiba-Chargi

294 CHAPTER 16 ABSTRACT Objectives Low skeletal muscle mass (SMM) and sarcopenic obesity (co-presence of low SMM and obe - sity) are emerging prognosticators in oncology, but the prevalence and prognostic value in oropharyngeal squamous cell carcinoma (OPSCC) is not yet known. Materials and methods Patients with OPSCC, curative treatment intention and pre-treatment diagnostic imaging of the head and neck area were included. Patients with unknown HPV-status, palliative treat - ment intention or unavailable imaging were excluded. Relevant demographic and clinical characteristics were collected between 2009-2016. Patients were stratified into a low-, in - termediate-, and high-risk group according to HPV-status, number of pack-years, tumor and nodal stage. SMMwas radiologically measured, and cutoff values were determined by optimal stratification. The prognostic value of low SMM and sarcopenic obesity for overall survival (OS) and disease-free survival (DFS) was determined by Cox regression analysis and Kaplan Meier survival curves. Results In 216 patients, low SMM and sarcopenic obesity were present in 140 (64.8%) and 13 (6.0%) patients, respectively. Onmultivariate analysis, stratification into a high-risk group (HPV-neg - ative status with ≥ 10-pack-years or T4-stage) was a prognostic factor for OS and DFS (HR 2.93, p<0.01) (HR 4.66, p<0.01). Of specific interest, sarcopenic obesity was a strong negative prognostic factor for OS and DFS (HR 4.42, p<0.01) and (HR 3.90, p<0.05), independent from other well-known prognostic factors such as HPV-status. Conclusion Low skeletal muscle mass is highly prevalent in OPSCC patients. Sarcopenic obesity is a novel pretreatment prognosticator for OS and DFS in OPSCC and should therefore be considered in clinical decision making.