Prognostic value of serum C-reactive protein level prior to second-line treatment in intermediate risk metastatic renal cell carcinoma patients

Background: The later-line treatment of metastatic renal cell carcinoma (mRCC) has been drastically changing by the development of immune-oncology drugs and molecular targeted treatment in recent years. Although the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model is useful for second-line setting, this model has the problem that over 50% patients are classified as intermediate risk group. The aim of this study is to evaluate whether the serum C-reactive protein (CRP) levels prior to second-line treatment could divide intermediate risk group patients. Methods: We retrospectively reviewed 82 consequent intermediate-risk mRCC patients who received second-line molecular targeted therapy. We classified patients who had serum CRP higher than 0.5 mg/dl in elevated CRP group because the median baseline serum CRP level before second-line treatment was 0.51 mg/dl. We assessed the prognostic impact of serum CRP levels prior to second-line treatment initiation to predict overall survival (OS). Results: Thirty-three out of 82 (40%) patients demonstrated elevated baseline CRP levels. The median OS of elevated and non-elevated CRP group was 11.5 (95% CI 5.4–17.5) and 29.4 (95% CI 25.5–33.5) months, respectively (p = 0.001). The serum CRP elevation could predict prognosis in intermediate risk patients treated with second-line treatment (HR 2.5, 95% CI 1.4–4.2, p = 0.001). Conclusions: The serum CRP levels after first-line treatment termination could divide intermediate risk group mRCC patients into two prognostic subgroups in second-line targeted treatment setting.