Prognostic value of preoperative lymphocyte to monocyte ratio in patients with nonmetastatic clear cell renal cell carcinoma

Growing evidence indicates that systemic inflammation involves in cancer development and progression. Preoperative lymphocyte to monocyte ratio (LMR) has been estimated as an independent prognostic factor of various cancers. We investigated the prognostic value of LMR in nonmetastatic clear cell renal cell carcinoma (ccRCC) patients after surgery. We retrospectively recruited 430 consecutive patients with nonmetastatic ccRCC (T1-3N0M0) who underwent curative nephrectomy between 2008 and 2009 at a single center in China. Lymphocyte and monocyte counts were obtained at hospitalization before surgery. Preoperative LMR as a continuous variable and as a dichotomized variable at a level of 3.25, which was the 25th percentile value, were analyzed in unvariable and multivariable Cox regression models, respectively. Concordance index (C-index) was calculated to assess predictive accuracy. Kaplan-Meier method was applied to compare survival curves. As both of the continuous and dichotomized variable, decreased preoperative LMR was proven to be independent prognostic factors of recurrence-free survival (P = 0.039 and P = 0.003, respectively) and overall survival (P = 0.002 and P < 0.001, respectively). Further examination revealed that the dichotomized LMR could enhance the predictive accuracy of each of the existing prognostic models among intermediate-risk to high-risk patients. The preoperative LMR is an independent prognostic factor of recurrence-free survival and overall survival for nonmetastatic ccRCC patients after surgery, and it can be used in tandem with established prognostic systems to further enhance outcome prediction in intermediate-risk to high-risk patients.