Systemic Inflammatory Biomarkers and Cancer-Associated Cachexia: A Narrative Review.

Cancer-associated cachexia (CAC) is a multifactorial syndrome characterized by systemic inflammation, muscle wasting, and progressive functional decline, affecting up to 80% of patients with advanced cancer. The inconsistent diagnostic criteria limit comparability across studies and hinder translation into clinical practice. Inflammatory biomarkers, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), and serum albumin, have been studied as markers of the presence, severity, and progression of CAC. This review synthesizes evidence linking these five biomarkers to key manifestations of CAC, including weight- loss, muscle depletion, fatigue, quality of life, and survival. A structured search of PubMed, Embase, and Web of Science studies published between 2000 and 2025, yielding 20 articles for final synthesis to evaluate biomarker patterns and their potential utility for early detection and risk stratification. IL-6 and CRP show consistent associations with muscle wasting and systemic inflammatory burden. Albumin and NLR demonstrate enhanced prognostic value when incorporated into composite indices such as the Cachexia index. TNF-α remains mechanistically relevant but shows limited predictive utility when assessed independently. CRP, Albumin, and NLR are derived from routine, low-cost tests, whereas IL-6 and TNF-α require specialized cytokine assays. Future research is warranted to standardize diagnostic criteria and validate biomarker thresholds to develop an accessible, multi-biomarker panel for improved detection and monitoring of CAC.