The Preoperative C-reactive Protein/Albumin Ratio of Immune-inflammation Index Is an Independent Prognostic Factor of Advanced Colorectal Cancer in Older Patients (≥ 65 years).

Objectives: We investigated the characteristics of colorectal cancer (CRC) in older patients (≥ 65 years) and the immune-inflammation indexes. Methods: This study included 149 patients aged ≥ 65 years with advanced colorectal cancer, who underwent radical surgery (R0 resection). Four immune-inflammation indexes (C-reactive protein-to-albumin ratio (CAR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and neutrophil-to-lymphocyte ratio (NLR)) were calculated. We analyzed the association between immune-inflammation indexes and clinicopathological features or prognosis. Results: Tumor depth and lymph node metastasis were independent prognostic factors for recurrence-free survival (RFS) in multivariate analysis (p=0.03, hazard ratio [HR] 2.095, 95% confidence interval (CI) 1.225-3.982 and p=0.008, HR 2.209, 95% CI 1.225-3.982, respectively). Lymphatic invasion and CAR were also independent prognostic factors for overall survival (OS) in multivariate analysis (p=0.04, HR 2.197, 95% CI 1.042-4.632 and p=0.04, HR 2.174, 95% CI 1.032-4.58, respectively). Lymphatic invasion and CAR were independent prognostic factors for cancer specific survival (CSS) in the multivariate analysis (p=0.03, HR 3.004, 95% CI 1.11-8.13 and p=0.03, HR 3.087, 95% CI 1.135-8.394, respectively). Conclusions: CAR is a useful immune-inflammation index for predicting the prognosis after radical resection for advanced CRC in older patients.