474 Background: White blood cell count (WBC) and C-reactive protein (CRP) are reliable biomarkers in clear cell renal cell carcinoma (ccRCC). Nevertheless, accepted cut-offs values for risk stratifications are missing. This study re-evaluated the prognostic and predictive significance of preoperatively WBC and CRP that independently predicts patient prognosis and to determine optimal cut-off values for CRP. Methods: 327 patients with surgery for ccRCC were retrospectively evaluated from 1996 to 2005. Cox-proportional hazard models were used, adjusted for the effects of tumor stage, tumor size, Fuhrman grade, and Karnofsky-Index; and to evaluate the prognostic significance of WBC and CRP; and to identify cut-off values. Identified cut-offs were correlated with clinico-pathological parameters and used to estimate cancer-specific survival (CSS). To prove any additional predictive accuracy of the identified cut-off it was compared to a clinico-pathological base model using Harrell c-index. Results: In univariable analyses WBC was a significant prognostic marker at a concentration of 9.5/µl (HR: 1.83) and 11.0/µl (HR: 2.09) and supported a CRP value of 0.25 mg/dL (HR: 6.47, p < 0.001) and 0.5mg/dL (HR: 7.15, p < 0.001) as potential cut-off values. If adjusted by the multivariable models WBC showed no clear breakpoint, but a CRP-value of 0.25mg/dL (HR: 2.80, p = 0.027) proved to be optimal. Reduced CSS was proven for CRP 0.25 mg/dL (median: 69.9 vs. 92.3 months). Median follow-up was 57.5 months with 72 (22%) tumor related deaths. The final model built by the addition of CRP 0.25mg/dL did not improve predictive accuracy (c-index = 0.877) than compared to the clinico-pathological base model (c-index =0.881) which included TNM-stage, grading and Karnofsky-Index. Conclusions: Multivariable analyses revealed an optimal breakpoint of CRP at a value of 0.25mg/dL best to stratify patients at risk of cancer-specific mortality, but CRP 0.25mg/dL added no additional information in the prediction model. Therefore we cannot recommend to measure CRP as the traditional parameters of TNM-stage, grading and Karnofsky-Index were already of high predictive accuracy.
Prognostic impact of serum C-reactive protein in metastatic clear-cell renal cell carcinoma patients treated with nivolumab
