C-reactive protein/albumin ratio of immune-inflammation index is associated with prognosis of colorectal cancer in older patients (≥ 65 years)

Abstract Purpose We investigated the characteristics of colorectal cancer (CRC) in older patients (≥ 65 years) and the immune-inflammation indexes that are useful for predicting postoperative prognosis. Methods This study included 153 patients aged ≥ 65 years with Stage I-Ⅲ colorectal cancer, who underwent radical surgery (R0 resection) in our hospital from 2016 to 2018. 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 Lymph node metastasis and venous invasion were independent prognostic factors for recurrence-free survival (RFS) in multivariate analysis (p = 0.04, hazard ratio [HR] 2.27, 95% confidence interval (CI) 1.028–4.999 and p = 0.03, HR 2.85, 95% CI 1.124–7.224, respectively). Lymph node metastasis and CAR were independent prognostic factors for overall survival (OS) in multivariate analysis (p = 0.04, HR 2.33, 95% CI 1.046–5.178 and p = 0.04, HR 2.45, 95% CI 1.054–5.672, respectively). Lymphatic invasion, venous invasion, and CAR were independent prognostic factors for cancer specific survival (CSS) in the multivariate analysis (p = 0.04, HR 3.04, 95% CI 1.028–8.988; p = 0.03, HR 10.46, 95% CI 1.339–81.72; and p = 0.02, HR 3.78, 95% CI 1.278–11.152, respectively). Conclusion CAR is a useful immune-inflammation index for predicting the prognosis after radical resection for CRC in older patients.