Impact of low skeletal muscle mass and density on outcomes of locally advanced esophageal cancer patients treated with radical radiotherapy.

Abstract Low skeletal muscle mass and density are independent predictors of clinical outcomes in multiple gastrointestinal cancers. However, its effect on the long-term survival of locally advanced esophageal cancer patients undergoing radical radiotherapy is still unclear. Methods Patients with stage II-III esophageal cancer undergoing radical radiotherapy, enrolled in a observational cohort study, were included. Skeletal muscle mass and density were measured on CT. Patients with high and low skeletal muscle mass and density were compared regarding overall survival (OS). Results 165 patients (75.8% males, median age 63) were included, from March-2012 to September-2017. Before radiotherapy, 26.7% patients had low skeletal-muscle-mass and 23.0% patients had low skeletal-muscle-density. After radiotherapy, 40.6% patients had low skeletal-muscle-mass and 30.3% patients had low skeletal-muscle-density.The median OS of high skeletal-muscle-mass/density group was significantly higher than that of low skeletal-muscle-mass/density group before radiotherapy (28.7 vs 28.2 months, p = 0.041; 29.6 vs 16.9 months, p = 0.025). The median OS of high skeletal-muscle-mass/density group was also significantly higher than that of low skeletal-muscle-mass/density group after radiotherapy (30.3 vs 20.3 months, P = 0.012; 29.6 vs 17.2 months, p = 0.018). Conclusion Low skeletal muscle mass and density are associated with long-term outcome in patients undergoing radical radiotherapy. It is suggested that oncologists should pay more attention to the management of muscle mass and density of patients with esophageal cancer undergoing radiotherapy in order to improve their nutritional status and long-term survival.