The prognostic value of C-reactive protein in renal cell carcinoma: a systematic review and meta-analysis

Objectives: C-reactive protein (CRP) has been reported to be associated with poorer prognosis in patients with renal cell carcinoma (RCC); however, conflicting results exist. We conducted a systematic review to evaluate the prognostic value, and a meta-analysis was done if the extracted data could be merged.

Materials and methods: We searched MEDLINE, EMBASE, and the Cochrane Central Search library for published studies that analyzed the effect of CRP in RCC. All included cases were categorized into 4 groups of different stages and tumor types for analysis, and the relationships between CRP and stage, grade, and survival were analyzed.

Results: Overall, 24 studies including 4,100 RCC cases were accepted for meta-analysis. Elevated CRP level was associated with higher stage (risk ratio [RR] 2.90, 95% confidence interval [CI] 2.52-3.32, P<0.00001) and higher grade (RR 4.31, 95% CI 3.35-5.56, P<0.00001) in the overall analysis of patients with all pathologic types of RCCs, and it was also associated with poorer overall survival (hazard ratio [HR] 1.51, 95% CI 1.09-1.93, P<0.00001) and cancer-specific survival (CSS) (HR 3.91, 95% CI 2.18-5.64, P<0.00001). In patients with localized RCC, elevated CRP level was associated with poorer CSS (HR 3.49, 95% CI 2.93-4.05, P<0.00001) and progression-free survival (HR 3.29, 95% CI 2.91-3.67, P<0.00001); whereas in patients with metastatic RCC, elevated CRP level was associated with poorer overall survival (HR 2.37, 95% CI 2.14-2.60, P<0.00001) and CSS (HR 3.70, 95% CI 3.19-4.22, P<0.00001). Specifically, in the patients with clear cell RCC, elevated CRP level was also associated with higher stage (RR 2.92, 95% CI 2.25-3.80, P<0.00001), poorer CSS (HR 2.60, 95% CI 2.32-2.88, P<0.00001), and poorer progression-free survival (HR 1.21, 95% CI 0.94-1.47, P<0.00001).

Conclusion: Elevated CRP level in a patient with RCC is associated with poorer prognosis, and it could serve as a useful biomarker for clinical prediction.