Lymphopenia as an independent predictor of worse survival in papillary renal cell carcinoma.

Abstract

397 Background: Lymphopenia signifies inflammatory response and is an index of poor systemic immunity which can be associated with poor survival outcomes. The aim of this study was to evaluate the prognostic relevance of preoperative absolute lymphocyte count (ALC) in patients with papillary renal cell carcinoma (RCC). Methods: We retrospectively analyzed our institutional, prospectively maintained, renal cancer database and identified patients with pathologic diagnosis of papillary RCC after partial or radical nephrectomy. Patients with preoperative ALC value within 3 months prior to surgery were eligible for the study. ALC of 1,300 cells/µl was used as the cutoff value (our lowest laboratory reference value). We evaluated the correlation between ALC and age, gender, Charlson comorbidity index (CCI), pathologic T stage, nuclear grade, and overall TNM stage. Differences in overall survival (OS) by ALC status were assessed using the log−rank test. Cox proportional hazards modeling was used for multivariable analyses. Results: We identified 314 out of 2,732 patients with a pathologic diagnosis of papillary RCC after partial or radical nephrectomy from 1997 to 2013. Those undergoing multiple surgical procedures (multifocal or bilateral disease) or missing preoperative ALC were excluded from the study. A total 205 patients met inclusion criteria with a median follow up of 37.3 months. As a continuous variable, low absolute lymphocyte count was associated with higher pT stage (p=0.038), TNM stage (p=0.029) and older age (p=0.022). Lymphopenia below 1,300 cells/µl was also associated with pT stage (p=0.008) and TNM stage (p=0.018). On multivariable analysis, independent of stage, older age,and CCI, lymphopenia was associated with inferior overall survival (HR 2.1 [CI 1.1−4.03], p=0.037). Conclusions: In our series of patients with papillary renal cell carcinoma, lymphopenia was associated with lower overall survival independent of stage, age,and charlson comorbidity index. ALC significantly increases the accuracy of already established prognostic factors and can be helpful for patient counseling and design of clinical trials.