The effect of lymph node ratio on the surgical outcomes in patients with colorectal cancer

The current study aimed to evaluate the effect of lymph node ratio (LNR) on the short-term and long-term outcomes of colorectal cancer (CRC) patients who underwent radical CRC surgery. We retrospectively collected CRC patients who underwent radical surgery from Jan 2011 to Jan 2020 in a single-center hospital. The patients were divided into the high LNR group and the low group according to the median. The baseline information and the short-term outcomes were compared between the high group and the low group. Univariate and multivariate logistic regression was performed to analyze the independent predictors for overall survival (OS) and disease-free survival (DFS). A 1:1 proportional propensity score matching (PSM) was used to reduce the selection bias between the two groups. Kaplan-Meier method was used to estimate the OS and DFS between the two groups in different T stages. A total of 1434 CRC patients undergoing radical surgery were enrolled in this study, and there were 730 (50.9%) patients in the low LNR group and 704 (49.1%) patients in the high LNR group. After the PSM, there were 618 patients in both groups, the baseline characteristics between the two groups had no significant difference (p > 0.05). After comparing the Surgery-related information and The Short-term outcomes, the high LNR group had a longer hospital stay (after PSM, p < 0.01). In univariate and multivariate logistic regression analyses, age (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), tumor location (univariate analysis, p = 0.020; multivariate analysis, p = 0.024), lymph-vascular space invasion (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), cancer nodules (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), tumor size (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), LNR (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), and overall complications (univariate analysis, p < 0.01; multivariate analysis, p < 0.01) were independent risk factors for OS, and age (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), tumor location (univariate analysis, p = 0.032; multivariate analysis, p = 0.031), T stage (univariate analysis, p < 0.01; multivariate analysis, p = 0.014), lymph-vascular space invasion (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), cancer nodules (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), LNR (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), and overall complications (univariate analysis, p < 0.01; multivariate analysis, p < 0.01) were identified as independent risk factors for DFS. The high LNR group had a worse OS in T3 (p < 0.01) and T4 (p < 0.01) as well as a worse DFS in T3 (p < 0.01) and T4 (p < 0.01). No association was found between LNR and postoperative complications, but the high LNR group had a longer hospital stay. LNR was identified as an independent predictor for OS and DFS. Furthermore, high LNR had a worse OS and DFS under T3 and T4 stages. Therefore, LNR was more prognostically significant for CRC patients under T3 and T4 stages.