151751-Najiba-Chargi

218 CHAPTER 12 ABSTRACT Background This study aims to investigate the predictive value of low skeletal muscle mass (SMM) for cetuximab dose-limiting toxicity (DLT) and its prognostic value in head and neck squamous cell carcinoma (HNSCC) patients treated with concomitant cetuximab and radiotherapy. Material and methods Patients diagnosed with HNSCC and treated with primary or adjuvant concomitant cetuximab and radiotherapy were included. Clinical and demographic variables were retrospectively re - trieved and SMMwas measured at the level of the third cervical vertebra using pre-treatment diagnostic computed tomography or magnetic resonance imaging. An optimal cut-off value for low SMMwas determined based on the lowest log likelihood associated with cetuximab DLT. A multivariate linear regression model was used to determine predictive factors for cetuximab DLT. The prognostic value of low SMM for disease-free and overall survival was analyzed using Kaplan-Meier curves. Results The optimal cut-off value for low SMM as a predictor of cetuximab DLT was an LSMI ≤ 45.2 cm 2 / m 2 . Of the 91 included patients, 74.7% had low SMM and 30.8% experienced cetuximab DLT. At multivariate analysis, low SMM had no predictive value for DLT (OR 0.83; 95% CI 0.27-2.56; p=0.74). The Kaplan-Meier curve demonstrated that patients with low SMM had significantly lower overall survival (Log Rank χ 2 = 5.87; p=0.02). Conclusion Low SMM is highly prevalent in HNSCC patients treated with concomitant cetuximab and ra - diotherapy. Low SMM has no predictive value for cetuximab DLT in HNSCC patients. Low SMM is probably not a prognostic factor for overall survival in highly selected HNSCC patients treat - ed with concomitant cetuximab and radiotherapy and unfit for platin-based chemotherapy.