Prognostic impact of cachexia in patients undergoing radical resection for colorectal cancer: a retrospective study

Background: Host and tumor factors influence tumor progression. Cachexia has attracted considerable attention as a potential host disease, and is a multifactorial syndrome characterized by skeletal muscle loss; however, it is difficult to objectively assess. The cachexia index (CXI) has been reported as a novel marker for assessing cachexia. This study investigated the relationship between cachexia and long-term prognosis after colorectal cancer surgery using the CXI. Methods : We included 299 patients who underwent radical surgery for colorectal cancer at Osaka City University Hospital between January 2017 and December 2019. CXI was originally calculated using the skeletal muscle index, serum albumin level, and neutrophil-to-lymphocyte ratio. This study also evaluated the P-CXI, which has a component of the psoas muscle index instead of the skeletal muscle index, and was calculated as follows: psoas muscle index (cm ² /m ² ) × serum albumin level (g/dL) / neutrophil-to-lymphocyte ratio. The prognostic value of P-CXI was investigated using univariate and multivariate Cox hazard regression models after adjusting for potential confounders. Results : The low P-CXI group included 185 patients with significantly shorter relapse-free survival (RFS) and overall survival (OS) than the high P-CXI group (p=0.002 and p=0.005, respectively). The multivariate analysis showed a significant reduction in RFS and OS, wherein the following were independent poor prognostic factors: age >70 years (hazard ratio [HR]: 2.051, 95% confidence interval [CI]: 1.104–3.807, p=0.022 and HR: 2.649, 95% CI: 1.172–5.990, p=0.019, respectively), T4 tumors (HR: 4.153, 95% CI: 1.869–9.233, p<0.001 and HR: 8.797, 95% CI: 3.185–24.29, p<0.001, respectively), preoperative carbohydrate antigen 19-9 >37 U/ml (HR: 2.827, 95% CI: 1.224–6.532, p=0.014 and HR: 5.578, 95% CI: 2.043–15.23, p<0.001, respectively), and low P-CXI (HR: 2.629, 95% CI: 1.312–5.266, p=0.006 and HR: 2.716, 95% CI: 1.064–6.933, p=0.036, respectively). Conclusion : Cachexia was shown to have a prognostic impact in patients with colorectal cancer who underwent radical resection, where P-CXI may be a useful prognostic marker.