151751-Najiba-Chargi

211 Systemic therapy: skeletal muscle mass and chemoradiotherapy bone marrow suppression) or a definite termination of chemotherapy after the first or second cycle of therapy. Despite slightly different definitions of CDLT, the conclusions of both studies were comparable: a threefold significant higher incidence of CDLT in SMM patients (35.7% vs. 10.1% and 44.3% vs. 13.7%). In both studies patients experiencing CDLT had a significantly lower overall survival than patients who did not. In the current study, we decided not to use a previously published multivariate formula to calculate CSMA at the level of L3, but rather use CSMA at the level of C3 directly to assess SMM. This better allowed us to formulate a sex-specific cut-off point for low SMM, as is commonly done in other areas of oncological research, rather than use a single cut-off point. It is known that women have less SMM than men. 36 . Sex is part of the previously published prediction formula for translation of CSMA at level of C3 to CSMA at level of L3 as such sex is implicitly already accounted for using this method. This choice does hinder direct comparison to our previous results. It should be noted that the incidence of low SMM as well as the trifold risk of CDLT in patients with low SMM is equal in both our previous (9) and this current study and compares to results in other studies. CONCLUSION This study validates the previous findings that pre-treatment low SMM is significantly asso- ciated with CDLT in LA-HNSCC patients treated with primary CRT with high dose cisplatin. Pre-treatment low SMM alone was not a prognostic factor for OS, but CDLT was. Routine SMM assessment may allow for CDLT risk assessment and identification of those patients who may benefit from treatment modifications and from interventions to increase SMM. 11