Background: Pretreatment C-reactive protein (CRP) level has been shown to be prognostic for metastatic renal cell carcinoma (mRCC).
Objectives: To demonstrate that CRP would be a biomarker for mRCC, we evaluated the impact of CRP kinetics on survival.
Design, setting, and participants: One hundred eight patients with mRCC were treated from 1994 to 2007 with a median follow-up period of 18 mo (interquartile range: 7-40 mo).
Intervention: All patients underwent multimodal therapeutic intervention.
Measurement: Patients were divided into three groups according to CRP kinetics. Patients whose pretreatment CRP levels were <5mg/l, patients whose pretreatment CRP levels were >5mg/l and normalized (<5mg/l) at least one time during treatment, and patients whose pretreatment CRP levels were >5mg/l and never normalized were assigned to nonelevated, normalized, and non-normalized CRP groups, respectively. The prognostic impact of CRP kinetics and the correlation between normalized CRP period and overall survival period were determined.
Results and limitations: In 61 of the 108 patients (56%), CRP levels were elevated at the diagnosis of mRCC. During treatment, CRP levels were normalized in 30 of 61 patients (49%), whereas CRP levels remained elevated in the remaining 31 patients. Overall survival rates were significantly different between nonelevated, normalized, and non-normalized CRP groups (p<0.001) with 2-yr survival rates of 69%, 55%, and 4%, respectively. In multivariate analysis, CRP kinetics was an independent significant factor for overall survival. Normalized CRP period was significantly correlated with overall survival period in 78 patients who died of disease. Since this is a small retrospective study on patients within the past era of immunotherapy, larger confirmatory studies in the current era of targeted therapy are needed.
Conclusions: CRP can be a novel, widely available biomarker for patients with mRCC.