151751-Najiba-Chargi

279 Systemic therapy: skeletal muscle mass changes and chemoradiotherapy At pre-CRT imaging, 141 patients (60%) had low SMM. As is shown in table 1, patients with low SMM were significantly more likely to be female, older of age, to be (current/former) smokers, to have combined tobacco and alcohol use, and to have a BMI <18.5 kg/m 2 . At follow-up imaging, 149 patients (63%) were diagnosedwith lowSMM. Mean SMA at follow-up imaging (31.62 cm 2 , SD 8.69) was significantly lower thanmean SMA at pre-CRT imaging (33.34 cm 2 , SD 9.11) (p<0.01). Table 2 shows the SMM changes that occurred in the study population. Only 91 patients (39%) had stable SMM compared to pre-CRT. A rather large proportion of the study population (n=129, 55%) had moderate loss in SMM compared to pre-CRT SMM and only 13 (6%) patients showedmoderate gain in SMM compared to pre-CRT SMM. A minority of patients experienced large loss in SMM (n=1, 0.4%) or large gain in SMM (n=1, 0.4%). Table 1. Study population characteristics Characteristic Total (n=235) Low SMM (n=141, 60%) Without low SMM (n=94, 40%) p -value N (%) N (%) N (%) Gender Male Female 164 (69.8) 71 (30.2) 73 (51.8) 68 (48.2) 91 (96.8) 3 (3.2) <0.01 Age diagnosis (years) (mean, SD) 58.6 (8.0) 59.9 (7.3) 56.7 (8.8) <0.01 BMI (kg/m 2 ) <18.5 18.5-24.9 25.0-29.9 ≥ 30 21 (8.9) 117 (49.8) 65 (27.7) 32 (13.6) 21 (14.9) 83 (58.9) 26 (18.4) 11 (7.8) 0 34 (36.2) 39 (41.5) 21 (22.3) <0.01 ACE-27 score None Mild Moderate Severe 50 (21.3) 115 (48.9) 53 (22.6) 17 (7.2) 31 (22) 67 (47.5) 33 (23.4) 10 (7.1) 19 (20.2) 48 (51.1) 20 (21.3) 7 (7.4) 0.95 Performance status ECOG 0 ECOG 1 ECOG 2 ECOG 3 Missing 63 (26.8) 111 (47.2) 26 (11.1) 1 (0.4) 34 (14.4) 35 (24.8) 68 (48.2) 16 (11.3) 0 22 (15.6) 28 (29.8) 43 (45.7) 10 (10.6) 1 (1.1) 12 (12.8) 0.56 Smoker No Current/former 43 (18.3) 192 (81.7) 20 (14.2) 121 (85.8) 23 (24.5) 71 (75.5) 0.05 Alcohol use No Yes 40 (17) 195 (83) 23 (16.3) 118 (83.7) 17 (18.1) 77 (81.9) 0.73 15