Body Subcutaneous Fat Change Predicts Chemoradiotherapy Response and Prognosis of Esophageal Cancer Patients: A Cohort Study

Background: Patients with esophageal cancer are prone to poor nutrition. Concurrent chemoradiation therapy (CCRT) may further influences body compositions including skeletal muscle (SM) and adipose tissue which are key indicators of nutritional status. This study aimed to evaluate whether body compositional change during CCRT could be a predictor of prognosis in esophageal cancer patients. Methods: From 2006 to 2018, esophageal cancer patients who received CCRT as initial treatment were consecutively enrolled. We assessed body compositions, including subcutaneous fat (SCF), intramuscular fat (IMF), and SM mass by measuring the cross-sectional area (CSA) of the fourth thoracic vertebral body on computed tomography (CT) scan. The body compositional change was assessed by comparing baseline and post-CCRT CSA. The association of body compositions and their changes during CCRT with patient prognosis was analyzed. Results: A total of 178 patients were enrolled with a mean baseline body mass index (BMI) of 22. After CCRT, there was a significant decrease in bodyweight (BW), SCF, IMF, and SM (P < 0.001). BMI and body compositions at baseline or post-CCRT were not significantly associated with patient prognosis. Patients with SCF loss during CCRT had significantly poorer CCRT response (OR 3.7, P < 0.001), shorter time to tumor progression (8.5 vs. 23.7 months, P = 0.011), and overall survival (13.7 vs. 25.9 months, P < 0.001) than patients with SCF gain/stable. IMF, SM, and BW change during CCRT did not correlate with CCRT response or survival. In multivariate Cox regression analysis, SCF change (HR 1.49, 95% CI: 1.03–2.14, P = 0.033) during CCRT was an independent predictor of survival after adjusting baseline BMI, cancer stage, treatment modality, and CCRT response. Conclusions: During the course of CCRT, SCF change is more sensitive than weight in assessing the nutritional status of esophageal cancer patients. SCF loss during CCRT is associated with worse CCRT response and survival in esophageal cancer patients.