Systemic Immune-Inflammation Index Predicts Tumor Recurrence after Radical Resection for Colorectal Cancer

The systemic inflammatory response is associated with tumor promotion and suppression. Accumulating evidence shows that peripheral blood markers of inflammatory response predict clinical outcomes in various human cancers. The aim of this study was to investigate the prognostic relevance of the inflammation-based biomarkers in colorectal cancer (CRC). We retrospectively analyzed 118 CRC patients who underwent curative resection between 2012 and 2017. The inflammation-based biomarkers were evaluated by using preoperative neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), systemic immune-inflammation index (SII), systemic inflammation values were assessed by the Kaplan-Meier analysis for cancer-specific recurrence-free survival (RFS) and Cox proportional-hazards model. There were significant differences in the levels of NLR, PLR, SII, and SIRI between recurrence and non-recurrence group. The area under the curve (AUC) for SII was 0.710, which showed the highest value in the inflammation-based biomarkers. Multivariate analysis identified that SII (p = 0.0031) and lymph node metastasis (p = 0.0168) were independent prognostic factors for recurrence. High SII exhibited more dismal RFS than low SII in CRC patients with non-metastatic lymph node (p = 0.0002). Our study suggests that SII and lymph node metastasis could be useful indicators in predicting the recurrence of CRC patients. Additionally, SII could accurately stratify CRC patients with tumor recurrence by combining with lymph node metastasis. This result would be beneficial for determining the optimal therapeutic strategies after surgical resection for CRC.