Muscle strength is associated with muscle mass in patients with esophageal cancer awaiting surgery

Background and Purpose: Decreased muscle mass and muscle strength are independent predictors of poor postoperative recov- ery in patients with esophageal cancer. If there is an association between muscle mass and muscle strength, physiotherapists are able to measure muscle strength as an early predictor for poor postoperative recovery due to decreased muscle mass. Therefore, in this cross-sectional study, we aimed to investigate the association between muscle mass and muscle strength in predominantly older patients with esophageal cancer awaiting esophagectomy prior to neoadjuvant chemoradiation. Methods: In patients with resectable esophageal cancer eligible for surgery between March 2012 and October 2015, we used computed tomographic scans to assess muscle mass and compared them with muscle strength measures (hand- grip strength, inspiratory and expiratory muscle strength, 30 seconds chair stands test). We calculated Pearson correla- tion coefficients and determined associations by multivariate linear regression analysis. Results and Discussion: A tertiary referral center referred 125 individuals to physiotherapy who were eligible for the study; we finally included 93 individuals for statistical analysis. Mul- tiple backward regression analysis showed that gender (95% confidence interval [CI], 2.05-33.82), weight (95% CI, 0.39- 1.02), age (95% CI, −0.91 to −0.04), left handgrip strength (95% CI, 0.14-1.44), and inspiratory muscle strength (95% CI, 0.08-0.38) were all independently associated with muscle surface area at L3. All these variables together explained 66% of the variability (R2) in muscle surface area at L3 (P < .01). Conclusions: This study shows an independent association between aspects of muscle strength and muscle mass in patients with esophageal cancer awaiting surgery, and phys- iotherapists could use the results to predict muscle mass on the basis of muscle strength in preoperative patients with esophageal cancer.