University of Groningen Low muscle mass is associated with early termination of chemotherapy related to toxicity in patients with head and neck cancer Sealy,

38 39 Background and aims: We studied whether low pre-treatment muscle mass, measured with 40 CT at thoracic (T4) or lumbar level (L3) associates with early termination of chemotherapy 41 related to toxicity in head and neck cancer (HNC) patients. 42 Methods: This was a retrospective chart and image review. Adult HNC patients treated with 43 (surgery and) platinum-based chemo-radiotherapy were included if a pre-treatment CT scan at 44 T4 or L3 level was available. Muscle mass was evaluated by assessment of skeletal muscle 45 index (SMI; cm/m). T4 and L3 SMI measurements were corrected for deviation from their 46 respective means and were merged into one score for SMI difference (cm/m). All cases were 47 assessed for presence of toxicity-related unplanned early termination of chemotherapy (‘early 48 termination’). Univariate and multivariate logistic regression models were used to investigate 49 associations between pooled SMI and early termination. 50 Results: 213 patients (age: 57.9±10.3 y, male: 77%, T4 image: 45%) were included. A 51 significant association between SMI as a continuous variable and early termination was 52 found, both in the univariate analysis (p=0.007, OR=0.96 [0.94-0.99]) and the multivariate 53 analysis (p=0.021, OR 0.96 [0.92-0.99]). The multivariate models identified potential 54 associations with type of chemotherapy, presence of co-morbidity, a combination of (former) 55 smoking and alcohol consumption, and sex. 56 Conclusion: Lower muscle mass was robustly associated with higher odds of early 57 termination of chemotherapy in HNC patients. Further prospective studies are required to 58 tailor the care for patients with low muscle mass and to avoid early termination of 59 chemotherapy. 60