A novel prognostic biomarker for cutaneous malignant melanoma: red cell distribution width (RDW) to lymphocyte ratio

It is well-known that inflammation plays a significant role in cancer formation and prognosis. Both lymphocyte count and red cell distribution width (RDW) has been used to predict prognosis in various cancers as an indicator of inflammation. Yet, the role of RDW-lymphocyte ratio (RLR) in determining prognosis is still unknown. We aimed to determine the prognostic role of RLR in cutaneous malignant melanoma (MM). One hundred fifteen patients with MM were included in the study retrospectively. The relationship of the clinical-pathological data with overall survival (OS) and progression-free survival (PFS) was analyzed using Kaplan-Meier curves. The cut-off values of neutrophil to lymphocyte ratio, systemic immune-inflammation index (SII), prognostic nutritional index (PNI) and RLR were determined as 2, 487, 51.5 and 6.52, respectively. OS was significantly longer in the low SII, high PNI, low RLR group, while PFS was longer in groups with high PNI and low RLR. In univariate analysis, it was determined that PFS was significantly correlated with Eastern Cooperative Oncology Group (ECOG) performance, TNM stage, PNI and RLR. Moreover, in univariate analysis, a significant correlation was determined between OS and age, ECOG performance, TNM stage, adjuvant interferon, SII, PNI and RLR. In multivariate analysis, ECOG performance, TNM stage and RLR were determined as independent prognostic factors for PFS, while TNM stage and RLR were found to be independent prognostic factors for OS. RLR could be a novel prognostic marker for both PFS and OS in patients with cutaneous MM.