Pre-treatment neutrophil-to-lymphocyte ratio predicts tumor pathology in newly diagnosed renal tumors.

Abstract

The neutrophil-to-lymphocyte ratio (NLR) predicts adverse outcomes after surgical treatment for clear cell renal cell carcinoma (ccRCC). However, its ability to distinguish aggressive from indolent renal tumors remains unknown. We therefore evaluated the association between NLR and pathologic outcomes at nephrectomy. From 1995 to 2008, 2402 patients underwent radical or partial nephrectomy for localized renal tumors. Of these, 2039 had an NLR within 90days prior to surgery. Comparisons of NLR by tumor size, histologic subtype, and nuclear grade were evaluated. Benign renal masses had a significantly lower NLR than malignant tumors (median 2.92 vs. 3.12; p=0.037) with the greatest difference noted among renal lesions >7cm (median 2.79 vs. 3.87; p<0.001). There was a significant difference in NLR among RCC subtypes (p=0.002), with cystic ccRCC demonstrating the lowest (median 2.48) and collecting duct RCC the highest NLR (median 5.99). Moreover, there was a significant increase in NLR with larger tumor size and greater nuclear grade (p<0.001). Specifically, in patients with ccRCC, an incremental increase in tumor size (≤4cm=2.80, >4 but ≤7cm=3.09 and >7cm=3.95) and nuclear grade (G1=2.68, G2=2.87, G3=3.48, and G4=5.18) was associated with greater NLR (p<0.001). An elevated NLR is associated with RCC pathology, higher-grade tumors, and more aggressive histologic subtypes at the time of nephrectomy. Therefore, NLR appears to be a preoperative marker of biologically aggressive RCC and may be useful in predicting malignancy and guiding management among patients with suspicious renal tumors.