Prognostic Impact of Cachexia Index in Patients Undergoing Surgery for Esophageal Cancer

BACKGROUND: Cachexia index (CXI) is a recently proposed biomarker reflecting the cachectic condition, including inflammation, sarcopenia and nutritional status, of patients with various malignancies. We evaluated its prognostic impact in patients undergoing esophagectomy for esophageal cancer (EC). METHODS: A total of 378 patients were retrospectively reviewed. CXI was calculated as skeletal muscle index × serum albumin level/neutrophil-to-lymphocyte ratio. The sex-specific lowest quartile defined the Low-CXI group. Univariate and multivariate Cox proportional hazards models were applied to identify independent prognostic factors for overall survival (OS) and disease-free survival (DFS). RESULTS: The low-CXI group was significantly associated with older age (P < 0.001), more severe comorbidity (P = 0.001), and more advanced pathological stage (P = 0.032). Patients in the low-CXI group had poorer OS and DFS than those in the high-CXI group (both P < 0.001). Multivariate analysis revealed that low-CXI was independently associated with poor OS (P = 0.002) and DFS (P = 0.002). In the cause-specific survival analyses, low-CXI was a predictor of deaths from non-EC-related causes. Subdivision into pathological stage (pStage) 0-I and II/III revealed that significant survival differences according to CXI were observed in both pStage 0-I (P = 0.045 for OS, and 0.029 for DFS) and pStage II/III (P < 0.001 for OS, and 0.002 for DFS) patients. CONCLUSIONS: Low-CXI was independently associated with poor OS and DFS in patients undergoing surgery for EC, in both early- and advanced-stage patients. Furthermore, CXI may also be useful for predicting non-EC-related mortality.