Association between masseter muscle sarcopenia and postoperative pneumonia in patients with esophageal cancer

Sarcopenia affects the swallowing and chewing muscles, such as the masseter muscle. However, the significance of masseter muscle loss in pneumonia remains unclear. We investigated the effects of masseter muscle sarcopenia (MMS) on postoperative pneumonia in patients with esophageal cancer. In this retrospective cohort study, we analyzed the data of 86 patients who underwent esophagectomy for stage I–III esophageal cancer at our hospital between March 2013 and October 2021. The primary endpoint was postoperative pneumonia within 3 months of surgery. MMS was defined as a (1) masseter muscle index (MMI) that was less than the sex-specific MMI cutoff values, and (2) sarcopenia diagnosed using the L3-psoas muscle index (L3-PMI). Postoperative pneumonia was noted in 27 (31.3%) patients. In multivariate analysis, FEV(1.0) < 1.5 L (odds ratio, OR: 10.3; 95% confidence interval, CI 1.56–67.4; p = 0.015), RLNP (OR: 5.14; 95%CI 1.47–17.9; p = 0.010), and MMS (OR: 4.83; 95%CI 1.48–15.8; p = 0.009) were independent risk factors for postoperative pneumonia. The overall survival was significantly worse in patients with pneumonia (log-rank: p = 0.01) than in those without pneumonia. Preoperative MMS may serve as a predictor of postoperative pneumonia in patients with esophageal cancer.