Impact of the Cachexia Index on survival and recurrence in patients undergoing surgery for gastric cancer

PURPOSE: This study aimed to elucidate the clinical relevance of the cachexia index (CXI), an integrative metric encompassing sarcopenia, nutritional status, and systemic inflammatory burden, in patients undergoing surgery for gastric cancer (GC). METHODS: We retrospectively reviewed 1,166 patients who underwent curative gastrectomy for GC. The CXI was calculated as follows: skeletal muscle index (SMI) × serum albumin concentration (g/dL) / neutrophil-to-lymphocyte ratio (NLR). Patients were dichotomized according to sex-specific lowest quartile cutoff values (61.6 for men and 49.2 for women). The impact of the CXI on overall survival (OS), disease-free survival (DFS), and the recurrence patterns was studied. Multivariate Cox regression analyses were performed to identify any independent predictive factors for a poor survival. RESULTS: A low CXI was significantly associated with advanced age (≥ 65 years), a higher comorbidity burden, an advanced pathological stage, and a higher incidence of postoperative complications. Patients in the low-CXI group had a significantly poorer OS than those in the high-CXI group (5-year OS: 63.4% vs. 78.5%, P < 0.001), with a consistently inferior survival across pathological stages I-III. A low CXI was also significantly associated with a poorer DFS (5-year DFS: 61.0% vs. 76.7%, P < 0.001). Among the patients with stage II/III disease, hematogenous recurrence occurred more frequently in the low-CXI group than in the high-CXI group (13.6% vs. 6.9%, P = 0.026). A multivariate analysis revealed that a low CXI was an independent predictor of a poor OS (HR 1.58, 95% CI: 1.20-2.07, P = 0.001). CONCLUSIONS: The CXI is useful for predicting the survival outcomes of GC patients, irrespective of tumor stage. A low CXI was associated with a higher incidence of recurrence, especially hematogenous recurrence.