Clinical significance of platelet count in patients with renal cell carcinoma.

During the last decades numerous prognostic factors have been studied for predicting survival of renal cell carcinoma (RCC). Platelet count has previously been reported to correlate with prognosis in RCC. The aim of the this study was to evaluate the significance of thrombocytosis in determining prognosis in patients with localized RCC who underwent radical nephrectomy. The study included 118 consecutive patients. Patients were divided into a normal platelet count group (group 1) and a thrombocytosis group (group 2) according to the preoperative platelet count. Thrombocytosis was defined as a platelet count greater than 400,000/microl. The data about stage distribution, grade, tumor size, histological subtype, hemoglobin level, Body Mass Index (BMI), age, ECOG score, gender, and survival rate of tumors between these two groups were compared. Survival estimates were compared with the Kaplan-Meier method and multivariate analysis was performed using a Cox model. The mean age of the patients was 61.4 years (range 30-78), and the mean follow-up period was 52.7 +/- 19.6 months (range 9-96). Thrombocytosis was present in 23 patients (19.49%). Fourteen (60.86%) of 23 patients with thrombocytosis died of disease progression. Patients with thrombocytosis had a worse prognosis than patients without thrombocytosis (p = 0.001). Thrombocytosis was noted in 8 (10.81%) of 74 patients with stage pT1-pT2 disease and in 15 (34.09%) of 44 patients with stage pT3-pT4 disease (p = 0.004). In univariate analysis, platelet count was correlated with T stage, hemoglobin level, lymph node positivity, ECOG score, and tumor size. Controlling for established prognostic indicators of pathologic stage, tumor size, platelet count, and lymph positivity using Cox's regression test, the difference in survival between the groups remained significant (p < 0.05). The platelet count can be considered a useful prognostic factor in patients with RCC who undergo radical nephrectomy.