1660 CRP-BASED CLASSIFICATION OF LOCALIZED RENAL CELL CARCINOMA PATIENTS INTO LOW, INTERMEDIATE, AND HIGH RISK OF MORTALITY

Abstract

INTRODUCTION AND OBJECTIVES: Approximately 30% of patients undergoing nephrectomy for localized Renal Cell Carcinoma (RCC) develop postoperative metastases. Preoperative C-reactive protein (CRP) is a robust predictor of outcomes. However, CRP cut-offs for Low, Intermediate, and High Risk groups have not been rationally derived. METHODS: 173 patients who underwent radical nephrectomy for localized RCC had CRP measured preoperatively. Receiver Operating Characteristics (ROC) curves were constructed to assess the potential of preoperative CRP to predict overall survival. ROC curves were used to determine the Area Under the Curve (AUC) and relative sensitivity and specificity of cut-offs. Based on these cut-offs, patients were categorized into Low, Intermediate, and High Risk groups. Kaplan-Meier survival curves were constructed to assess the impact of different cut-offs on overall survival. RESULTS: Preoperative CRP exhibited an AUC (95% CI) of 0.815 (0.718–0.911) (p 0.001). Three potential low risk (2.0, 3.0, and 4.0 mg/L) and three potential high risk (10.0, 15.0, and 25.0 mg/L) cut-offs were studied (Figure 1). The cut-offs 4.0 mg/L and 10.0 mg/L were the most discriminating based on population size and death frequency. Based on these cut-offs, patients were stratified into three categories: Low Risk (CRP: 4.0 mg/L), Intermediate Risk (CRP: 4.1–10.0 mg/L), and High Risk (CRP: 10.0 mg/L) Median (95% CI) survival for Low, Intermediate, and High Risk patients was 43.4 (42.2– 44.6) months, 41.8 (38.6–45.1) months, and 31.4 (39.8–43.4) months, respectively. K-M curves showed significant difference in survival among stratifications (Figure 2). Log-rank p-values were calculated comparing: Low Risk versus High Risk (p 0.001), Low Risk versus Intermediate Risk (p 0.06), Intermediate-Risk versus High Risk (p 0.009). CONCLUSIONS: Preoperative CRP is a robust molecular marker for predicting outcomes in patients undergoing potentially curative nephrectomy for localized RCC. This tool’s use can be increased through trinary categorization. Clinicians may wish consider the outcome differences among these distinct groups in preoperative counseling, postoperative management, and clinical guidelines. Source of Funding: None