Objective To investigate whether sarcopenia before concurrent chemoradiotherapy is prone to grade≥3 acute adverse reactions (AAR) and shorten survival in patients with advanced esophageal squamous cell carcinoma (ESCC).

Methods Data of advanced patients with pathologically diagnosed ESCC and CCRT (FP regimen) from August 2018 to July 2022 were reviewed retrospectively.Skeletal muscle mass and body composition were measured using pre-treatment CT images, and patients were divided into sarcopenia and non-sarcopenia groups.Grade≥3 AAR was diagnosed based on CTCAE5.0 and acute radiation injury criteria of the US RTOG.Risk factors for developing grade≥3 AAR were analyzed, and survival rates were calculated by Kaplan-Meier method.

Results Among 132 patients with ESCC (87 in the sarcopenia group and 45 in the non-sarcopenia group), 23(17.4%) experienced grade≥3 AAR.In multivariate regression analysis, independent risk factors for grade ≥3 AAR included the following: sarcopenia (OR: 6.034, 95%CI: 1.206-30.190, P=0.029), decreased SMD (OR: 0.693, 95%CI: 0.492-0.976, P=0.036), decreased SMI (OR: 0.841, 95%CI: 0.721-0.982, P=0.028), and increased FMI (OR: 2.433, 95%CI: 1.194-4.958;P=0.014).The OS rates were 16.01 months (95%CI: 14.89-17.13) in the sarcopenia group and 19.27 months (95%CI: 14.45-24.09) in the non-sarcopenia group (χ²=5.326, P=0.021) as well as 14.86 months (95%CI: 11.30-18.42) for patients with grade≥3 AAR and 16.67 months (95%CI: 14.91-18.43) for patients with grade 0-2 AAR (χ²=5.47, P=0.019).Among patients with grade≥3 AAR, the OS rates were 12.13 months (95%CI: 10.15-14.11) in the sarcopenia group and 18.69 months (95%CI: 12.85-21.88) in the non-sarcopenia group (χ²=4.466, P=0.035).

Conclusion Sarcopenia, decreased skeletal muscle density, and increased fat mass are important predictors of grade≥3 AAR.The OS of patients with sarcopenia and grade≥3 AAR may be reduced.