Relationships among body composition, muscle strength, and sarcopenia in esophageal squamous cell carcinoma patients.

Purpose: Relationships among body composition indices assessed by various modalities remain to be addressed in patients with esophageal squamous cell carcinoma (ESCC), in whom being underweight is more strikingly prevalent than in those with other malignancies. We investigated the relationships of body composition parameters with the sarcopenia prevalence of ESCC patients.
Methods: In this prospective study, we analyzed preoperative data obtained from 75 ESCC patients undergoing esophagectomy. Body composition data included body mass index (BMI), skeletal muscle index (SMI) assessed by computed tomography, and parameters calculated by bioelectrical impedance analysis (skeletal muscle mass (SMM), body fat mass). Muscle strength was evaluated by handgrip strength (HGS). Sarcopenia was defined as having both low SMI and low HGS.
Results: The median BMI value was 22.5 (range 15.2-28.7) in our ESCC cohort. BMI correlated significantly with fat mass (r = 0.84, P < 0.001), SMM (r = 0.57, P < 0.001) and SMI (r = 0.49, P < 0.001). Similarly, SMI showed a significant correlation with SMM (r = 0.45, P < 0.001). Meanwhile, HGS was highly correlated with SMM (r = 0.67, P < 0.001), while showing significant but weak associations with both BMI and SMI (r = 0.33, 0.34, respectively, P < 0.001). Notably, sarcopenia prevalence differed markedly according to BMI category; 28.6%, 12.2%, and 0% in the low (< 20), medium (20-25), and high (> 25) BMI groups, respectively.
Conclusions: BMI reflects comprehensive information on body composition in ESCC patients, although its correlation with muscle mass and muscle strength was moderate. Decreased BMI might serve as an indicator for sarcopenia in this population, in which the presence of sarcopenic obesity is rare.