Abstract: Objective:To investigate the association of preoperative neutrophil-lymphocyte ratio combined with platelet-to-lymphocyte ratio (NLR-PLR) score with clinicopathological parameters and prognosis in patients with colorectal cancer.
Methods:The retrospective cohort study was conducted. The clinicopathological data of 178 patients with colorectal cancer who were admitted to the First Affiliated Hospital of China Medical University from January 2013 to December 2014 were collected. There were 101 males and 77 females, aged from 21 to 90 years, with an average age of 63 years. All patients underwent radical resection of colorectal cancer. Observation indicators: (1) cutoffs of NLR and PLR and correlation between them; (2) association between preoperative NLR-PLR score and clinicopathological characteristics of patients with colorectal cancer; (3) follow-up and survival; (4) analysis of the risk factors for prognosis of patients with colorectal cancer. Follow-up was performed once every 3 months using outpatient examination or telephone interview including tumor markers, computed tomography and enteroscopy to detect postoperative survival of patients up to June 2017. Overall survival time was defined as the date of surgery to the date of the last valid follow-up or the date of death. Measurement data with skewed distribution were expressed as M (range). Count data were expressed as absolute numbers, and comparison between groups was performed using the chi-square test. Comparison of ordinal data was performed using the Mann-Whitney U test. Kaplan-Meier method was used to draw survival curve, and Log-rank test was used for survival analysis. The COX proportional hazard model was used for univariate and multivariate analyses.
Results: (1) Cutoffs of NLR and PLR and correlation between them. Receiver working characteristics of NLR and PLR showed that the NLR had a cutoff of 2.7 ［area under curve (AUC)=0.739, 95% confidence interval (CI): 0.638-0.841, P<0.05］ and PLR had a cutoff of 246 (AUC=0.640, 95%CI: 0.521-0.758, P<0.05). There was a correlation between NLR and PLR (r=0.712, P<0.05). (2) Association between preoperative NLR-PLR score and clinicopathological characteristics of patients with colorectal cancer. Results of preoperative NLR-PLR score showed that the NLR-PLR score was 0, 1, and 2 in 99, 52, and 27 patients, respectively. There were significant differences in tumor diameter, degree of tumor invasion, TNM staging, Dukes staging, and distant metastasis between patients with different preoperative NLR-PLR scores (x²=11.294, 10.816, 9.802, 9.525, 8.759, P<0.05). (3) Follow-up and survival: 178 patients were followed up for 1-53 months, with a median follow-up time of 37 months. The average survival time was 37 months for all the 178 patients, 50 months for 99 patients with NLR-PLR score of 0, 44 months for 52 patients with NLR-PLR score of 1, and 35 months for 27 patients with NLR-PLR score of 2. There was a significant difference in survival time between patients with NLR-PLR score of 0 and patients with NLR-PLR score of 1 (x²=6.388, P<0.05), between patients with NLR-PLR score of 0 and patients with NLR-PLR score of 2 (x²=26.388, P<0.05), between patients with NLR-PLR score of 1 and patients with NLR-PLR score of 2 (x²=5.350, P<0.05). (4) Analysis of the risk factors for prognosis of patients with colorectal cancer. Results of univariate analysis showed that degree of tumor invasion, TNM staging, Dukes staging, distant metastasis, NLR-PLR score, and platelet-NLR score were related factors for prognosis of patients with colorectal cancer ［hazard ratio (HR)=2.439, 2.472, 2.221, 9.020, 2.671, 2.099, 95%CI: 1.443-4.124, 1.413-4.323, 1.282-3.849, 4.449-18.082, 1.742-4.097, 1.339-3.290, P<0.05］. Results of multivariate analysis showed that degree of tumor invasion, distant metastasis, and NLR-PLR score were independent factors for prognosis of patients with colorectal cancer (HR=2.045, 5.641, 2.271, 95%CI: 1.051-3.979, 2.590-12.288, 1.185-4.354, P<0.05).
Conclusions:The preoperative NLR-PLR score is associated with tumor diameter, degree of tumor invasion, TNM staging, Dukes staging, and distant metastasis in patients with colorectal cancer. Patients with higher score have larger tumor diameter, higher degree of tumor invasion, higher stage, and easier distant metastasis. Preoperative NLR-PLR score can effectively evaluate the prognosis of patients with colorectal cancer. Patients with higher NLR-PLR score have shorter survival time. The NLR-PLR score is an independent influencing factor for prognosis of patients with colorectal cancer.