Platelet-to-lymphocyte Ratio (PLR) as an Indicator of Survival in Rare Histopathological Subtypes of Renal Cell Carcinoma

Objective: Inflammatory markers have prognostic significance for renal cell carcinomas (RCC) as in many types of cancer. The prognostic effect of inflammatory markers in the rare histological subtypes of RCC has not been adequately evaluated. In our study, we aimed to evaluate the relationship between basal inflammatory indices (neutrophil to lymphocyte ratio [NLR], platelet to lymphocyte ratio [PLR], lymphocyte to monocyte ratio [LMR], and systemic immune-inflammation [SII]) and survival (progression-free survival [PFS] and overall survival [OS]). Material and Methods: Patients with metastatic non-clear cell RCC (nccRCC) or RCC with sarcomatoid differentiation (sRCC) were included in the study. The relationship between inflammatory indices, which was calculated before any systemic treatment and survival, were retrospectively assessed. Results: Thirty patients, predominantly males (n = 20, 66.7%), with a median age of 59.1 (IQR, 52.5-70.3) years, were included in the study. Median PFS achieved with first-line tyrosine kinase inhibitors for patients with a PLR level less or greater than the median value (238) was 12.6 (95% CI 1.4-23.9) months and 4.8 (95% CI, 2.3-7.3) months, respectively (p = 0.021). Median OS for patients with a PLR level less or greater than the median (238) was 16.7 (95% CI, 3.7-29.7) months and 8.6 (95% CI, 4.9-12.3) months (p = 0.008), respectively. In the Cox-regression model (including gender, age, presence of metastasis at diagnosis, NLR, PLR, LMR, SII) only PLR was the independent predictive factor for both PSF (HR = 0.131; 95% Cl 0.028-0.620, p = 0.010) and OS (HR = 0.199; 95% Cl 0.048-0.819, p = 0.025).