Validation of CRP as prognostic marker for renal cell carcinoma in a large series of patients

Abstract

Background: To evaluate the prognostic significance of the pre-operative C-reactive protein (CRP) serum level in patients with renal cell cancer (RCC).

Methods: We evaluated 1,161 RCC patients with complete patient and tumour specific characteristics as well as information about their pre-operative CRP-level, who had undergone either radical nephrectomy or nephron-sparing surgery at two German high-volume centres (University Hospitals of Hannover and Ulm). The mean follow-up was 54 months.

Results: The CRP-level, stratified to three subgroups (CRP ≤ 4, 4-10, and >10 mg/l), correlated significantly with tumour stage (p < 0.001), the risk of presenting nodal disease (2.1, 3.1, and 16.4%) and distant metastasis (2.9, 8.6, and 30.0%; p < 0.001). The Kaplan-Meier 5-year cancer specific survival (CSS) rates were 89.4, 77.9, and 49.5%, respectively (p < 0.001). Multivariate analysis identified CRP as an independent prognosticator for CSS as well as overall survival (p < 0.001). Patients with a CRP of 4-10 and >10 mg/l had a 1.67 and 2.48 fold higher risk of dying due to their RCC compared to those with a pre-operative CRP ≤4 mg/l, respectively.

Conclusions: A high preoperative serum CRP level is an independent predictor of poor survival in patients with RCC. Its routine use could allow better risk stratification and risk-adjusted follow-up of RCC patients.

Figure 1

a) Cancer-specific survival (Kaplan-Meier) for all RCC patients plotted against the pre-operative CRP-group. The 5-year survival rate was 89.4%, 77.9%, and 49.5% for all evaluable patients (n = 1,047) with a CRP of ≤4 mg/l (n = 558), 4–10 mg/l (n = 141), and >10 mg/l (n = 348), respectively (p < 0.001, log rank). b) Overall survival (Kaplan-Meier) for all RCC patients plotted against the pre-operative CRP-group. The 5-year survival rate was 85.5%, 71.1%, and 46.3% for all evaluable patients (n = 1,133) with a CRP of ≤4 mg/l (n = 603), 4–10 mg/l (n = 158), and >10 mg/l (n = 372), respectively (p < 0.001, log rank).

Figure 2

a) Cancer-specific survival (Kaplan-Meier) for organ-confined RCC plotted against the pre-operative CRP-group: The 5-year survival rate was 93.2%, 86.9%, and 77.0% for all evaluable patients (n = 634) with a CRP of ≤4 mg/l (n = 437), 4–10 mg/l (n = 93), and >10 mg/l (n = 104), respectively (p < 0.001, log rank). b) Cancer-specific survival (Kaplan-Meier) for advanced RCC plotted against the pre-operative CRP-group: The 5-year survival rate was 76.3%, 58.0%, and 35.9% for all evaluable patients (n = 399) with a CRP of ≤4 mg/l (n = 114), 4–10 mg/l (n = 47), and >10 mg/l (n = 238), respectively (p < 0.001, log rank).