Preoperative lymphocyte-monocyte ratio ameliorates the accuracy of differential diagnosis in non-metastatic infiltrative renal masses

Purpose: Distinguishing infiltrative renal cell carcinoma (RCC) from transitional cell carcinoma (TCC) is a challenging issue due to their radiologic similarities. We evaluated systemic inflammatory biomarkers as parameters for distinguishing tumor types. Materials and Methods: A computerized search of medical records from November 2005 to October 2015 identified 116 patients with infiltrative renal masses who were difficult to diagnose confirmatively in radiological study. We investigated the diagnostic efficacy among these patients with their preoperative absolute neutrophil counts (ANC), absolute lymphocyte counts (ALC), absolute monocyte counts (AMC), neutrophil-lymphocyte ratio (NLR), and lymphocyte-monocyte ratio (LMR). Results: The infiltrative RCC group demonstrated significantly lower ALC {1449/μL (1140–1896), median [interquartile range (IQR)]} than the TCC group [1860/μL (1433–2342), p=0.016]. LMR [median (IQR)] also was lower in the infiltrative RCC group [2.98 (2.32–4.14) vs. TCC group 4.10 (2.86–6.09); p=0.011]. In subgroup analysis, non-metastatic infiltrative RCC showed lower ALC and LMR and higher NLR than non-metastatic TCC. Within non-metastatic infiltrative renal masses, multivariate logistic regression analysis revealed that younger patient age and lower LMR were associated with infiltrative RCC [odds ratios (OR) 0.874, p=0.024 and OR 0.461, p=0.048, respectively]. Receiver operating characteristic curve analysis showed that younger age and lower LMR were highly predictive of non-metastatic RCC (area under the curve=0.919, p<0.001). Conclusion: Age and LMR were significantly different between patients with infiltrative renal mass. These are potential markers for distinguishing between infiltrative RCC and TCC without metastasis.