Prognostic value of Platelet-to-Lymphocyte Ratio (PLR) and IL-6 in patients with small cell lung cancer

Abstract

Background: In order to identify patients with the most favourable prognosis, the effect of baseline level of interleukin-6 (IL-6) and platelet-to-lymphocyte ratio (PLR) on survival was analysed in patients with small cell lung cancer.<br>Material and Methods: 159 patients with small cell lung cancer were enrolled. Full blood count enabling computing the PLR, as well as NSE, ProGRP and IL-6 levels were done in all participants.<br>Results: We demonstrated significant effect of disease stage, performance status, sex, initial NSE, ProGRP and IL-6 levels as well as PLR on survival of patients with SCLC. In subgroups with normal initial levels of ProGRP (below 50.36 ng/L) and NSE (below 20.95 μg/L), the IL-6 level above 6.0 ng/L worsens the prognosis by 28% and 29%, respectively. In a subgroup with elevated initial ProGRP, the difference in survival between patients with normal vs elevated IL-6 level at baseline was 25%, whereas in a subgroup with elevated initial NSE it was 14%. The between-subgroup differences in PLR were less considerable. There was a significant effect of PLR on patient survival in a subgroup with normal initial NSE level and elevated initial ProGRP level.<br>Conclusion: In subgroups of SCLC patients identified based on initial tumour marker levels, IL-6 level can be a source of reliable prognostic information, whereas the effect of PLR is less marked. Patients with normal tumour marker levels and IL-6 below 6 ng/L at baseline have the most favourable prognosis.