Prognostic Impact of Cachexia in Patients Undergoing Radical Resection for Colorectal Cancer: A Retrospective Study.

Purpose: Tumor progression is influenced by both tumor-intrinsic and host-related factors. Among the latter, cachexia-a multifactorial syndrome involving progressive skeletal muscle loss-has garnered increasing attention for its prognostic relevance. However, objective assessment of cachexia remains difficult. The cachexia index (CXI) has emerged as a novel biomarker for its evaluation. This study aimed to assess the relationship between cachexia and long-term prognosis following curative surgery for colorectal cancer (CRC) using a modified index.

Methods: We retrospectively analyzed 298 patients who underwent curative colorectal cancer resection at Osaka City University Hospital between January 2017 and December 2019. A modified version of CXI, termed the P-CXI, was calculated using the psoas muscle index (cm²/m²), serum albumin (g/dL), and neutrophil-to-lymphocyte ratio (NLR): P-CXI = (psoas muscle index × albumin) / NLR. Patients were stratified into high and low P-CXI groups. Prognostic value for relapse-free survival (RFS) and overall survival (OS) was evaluated using univariate and multivariate Cox regression analyses.

Results: The low P-CXI group (n = 170) had significantly shorter RFS and OS compared to that of the high P-CXI group (p = 0.001 and p < 0.001, respectively). Multivariate analysis identified low P-CXI as an independent poor prognostic factor for RFS (HR: 2.627, 95% CI 1.363-5.063, p = 0.004) and OS (HR: 5.370, 95% CI 1.806-15.96, p = 0.002), along with older age, T4 tumors, and elevated CA 19-9.

Conclusion: Cachexia, as quantified by P-CXI, was significantly associated with worse long-term outcomes after curative CRC resection. P-CXI may serve as a simple and objective prognostic marker.