Predictive Value of Neutrophil-to-Lymphocyte Ratio(NLR) and Platelet-to-Lymphocyte Ratios (PLR) for Lymph Node Metastasis in Rectal Cancer Patients: a retrospective cohort study

Introduction: Systemic inflammatory response (SIR) indicators are predictive factors for lymph node metastasis(LNM) in various cancers. This study aimed to investigate the assiociation of platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) with LNM in rectal cancer(RC). In addition, we sought to explore the clinicopathological factors of LNM. Methods: We included 181 patients with RC admitted for surgery. NLR and PLR were calculated by collecting and analyzing preoperative blood samples, and their optimal cutoff values were analyzed using receiver operating characteristic (ROC). We examined the relationship between NLR or PLR and the clinicopathological characteristics of the patients, assessed their impact on LNM using ROC curve analysis. The risk factors for LNM were evaluated using both univariate and multivariate analyses. Results: high PLR (H-PLR) group exhibited higher rates of perineural invasion (PNI) at 54.2% (83/153), lymphovascular invasion (LVI) at 51.6% (79 /153),more elevated CEA(66/153,43.1%) and tumor deposits (TDs) at 14.4% (22/153). Additionally, this group demonstrated a greater incidence of LNM at 52.9% (81/153) and presented with a more advanced stage (stage II and stage III 124/153,81%). H-PLR were correlated with the presence of LNM, while H-NLR did not show it. The findings indicated that advanced T stage, high H-PLR, positive LVI, positive PNI, positive TDs, an increased number of cleared total lymph nodes (TLN), as well as elevated levels of carcinoembryonic antigen (CEA) and cancer antigen 19-9 (CA19-9) were associated with lymph node metastasis (LNM) according to univariate analysis. However, multivariate analysis revealed that only LVI and PNI were independent risk factors for LNM. Conclusion: H-PLR may be associated with unfavorable histopathological characteristics, positive LVI and PNI were independent risk factors for LNM in RC.