Prognostic significance of the CRP–albumin–lymphocyte (CALLY) index in esophageal cancer: systematic review and meta-analysis

Background and Objective Esophageal cancer (EC) is associated with marked regional disparities, poor 5-year survival (15%–25%), and limited progress in therapeutic outcomes. The tumor, node, and metastasis (TNM) staging system has reduced accuracy for long-term survival prediction, particularly after neoadjuvant therapy. The C-reactive protein–albumin–lymphocyte (CALLY) index—integrating inflammation (C-reactive protein), nutrition (albumin), and immunity (lymphocytes)—emerges as a novel prognostic biomarker. This study aims to evaluate its association with survival outcomes in patients with EC. Methods Following the PRISMA guidelines and PROSPERO registration (CRD420251125031), two researchers independently screened and extracted data from all relevant original articles published from database inception to July 2025. Study quality was assessed using the Newcastle-Ottawa Scale (NOS) score. Meta-analysis was performed using RevMan 5.3 software, and the risk of bias was assessed using risk of bias plots and funnel plots. Results Seven studies involving 2,243 patients were included in this meta-analysis. Pooled multivariate analyses of the included studies demonstrated that the CALLY index was independently associated with 5-year overall survival (OS) and recurrence-free survival (RFS), with a high CALLY index consistently predicting favorable outcomes. Moreover, patients with EC in the high CALLY index group had better 5-year OS and RFS than those in the low CALLY index group. Conclusion The pretreatment CALLY index is a robust prognostic biomarker that is independently associated with improved OS and RFS in patients with EC.