Lymphopenia is an Independent Predictor of Inferior Outcome in Clear Cell Renal Carcinoma

Purpose: A low absolute lymphocyte count is a likely index of poor systemic immunity that may be associated with aggressive features and inferior survival in patients with clear cell renal cell carcinoma. Materials and Methods: To determine the absolute lymphocyte count we retrospectively analyzed the preoperative blood count of 430 patients with a mean age of 60 years treated with primary surgical resection at our cancer center. Absolute lymphocyte count values as a continuous variable and at a level below 1,300 cells per mu l, which was our lowest reference value, were correlated with nuclear grade, pathological stage and TNM stage. We used the Kaplan-Meier method to estimate overall survival, stratified by absolute lymphocyte count status. Results: As a continuous variable, low absolute lymphocyte count was associated with higher grade (p = 0.009), and higher pT stage (p = 0.034) and TNM stage (p<0.0001). Lymphopenia below 1,300 cells per, mu l. was associated with high grade (p = 0.0043), pT stage (p = 0.051) and TNM stage (p<0.0001). At a median followup of 33.5 months lymphopenia was associated with inferior overall survival in a univariate model (p<0.0001), and on multivariate analysis independent of pT, N and M stages, patient age, grade, smoking history and comorbidities (p = 0.0102). Lymphopenia was also associated with inferior overall survival in a subset of young patients (age 60 years or less) with no distant metastasis (p = 0.014). Conclusions: In 430 patients with clear cell renal cell carcinoma lymphopenia was associated with lower overall survival independent of pT and TNM stages, nuclear grade, age, tobacco smoking and comorbidity index.