151751-Najiba-Chargi

319 Systemic therapy: skeletal muscle mass and functional outcomes linear-by-linear approximation of the Pearson’s Chi-square test (exact two-sided p -value) for ordinal data and the Fisher’s exact test for dichotomous data. P values were adjusted for tumor and treatment characteristics (T and N classification, treatment andmodified diet at t 0 for differences in HPV classification and AJCC stage and modified diet at t0 for sarcopenia) by means of multivariable logistic or linear regression analyses. Results were considered statis - tically significant when the p value was less than .05. For all post-hoc pairwise comparisons, a p value less than .01 was considered statistically significant. RESULTS Between January 2013 and September 2018, 248 patients with stage III-IV oropharyngeal squa - mous cell carcinomas were curatively treated with RT (+) at our institute of whom 106 patients were excluded from these analyses. Twenty-two patients were excluded because of previous treatment in the head and neck area ( n = 7), a second primary tumor elsewhere ( n = 14) or not speaking Dutch ( n = 1). Eighty-four patients were eligible, but were excluded because of un - available outcome data, due to several reasons: patient canceled pretreatment appointment ( n = 4), appointment was not made ( n = 40) or appointment was made, but assessments were not obtained ( n = 40). Baseline characteristics of these 84 patients are shown in table 1 and showed no significant differences with the included patients. Percentages of patients not included in the data assessment per accrual year are presented in figure 1. This figure also shows that the accrual increased from 19% in 2013 to 85% in 2018, with a slight decrease to 79% in 2019. Prevalence of functional impairment was comparable between patients included in 2013-2014 and 2017-2018 (appendix 1). Appendix 1. Functional outcomes at t1 and t2 stratified by inclusion year. P values shown for multivariable regression adjusted for AJCC stage and modified diet at t0. t 1 t 2 2013/2014 n = 14 2017/2018 n = 40 2013/2014 n = 14 2017/2018 n = 29 Swallowing outcomes Modified diet (FOIS < 7) No 9 (64) 26 (67) 13 (93) 20 (69) Yes 5 (36) 13 (33) 1 (7) 9 (31) Unknown 0 1 0 0 SWAL-QOL total score (0–100) Median (range) 21 (0-37) 20 (0-77) 10 (0-26) 6 (0-37) SWAL-QOL ≥ 14 No 3 (43) 10 (42) 9 (75) 17 (77) Yes 4 (57) 14 (58) 3 (25) 5 (23) Unknown 7 16 2 7 Trismus outcomes Mouth opening in mm Median (range) 46 (30-59) 44 (27-52) 44 (10-58) 43 (25-52) 17