C-reactive protein: A biomarker of survival in patients with metastatic renal cell carcinoma treated with subcutaneous interleukin-2 based immunotherapy

Purpose: In patients with metastatic renal cell carcinoma treated with low dose subcutaneous interleukin-2 based immunotherapy we evaluated a panel of biohumoral and clinical parameters before treatment to verify their correlation with clinical outcome. Materials and Methods: We analyzed the records of 110 patients treated at our institution. Before treatment total lymphocytes, lactate dehydrogenase, the erythrocyte sedimentation rate, albumin, C-reactive protein (CRP) and fibrinogen were analyzed and correlated with clinical parameters, namely performance status, patient age, sex, prior nephrectomy, number and sites of disease, and disease-free interval (DFI) from nephrectomy to metastatic disease. Results: Median survival was 12 months (partial and complete response 33, stable disease 14 and progression 7). The overall response was 24% for a partial and complete response, 37% for stable disease and 39% for progression. On univariate analysis good performance status (p = 0.0000), prior nephrectomy (p = 0.0001), DFI longer than 12 months (p = 0.0003), bone disease site (p = 0.0013), a low number of metastatic sites (p = 0.0449), normal albumin (p = 0.0001), low/normal fibrinogen (p = 0.0140), low/normal lactate dehydrogenase (p = 0.0430) and low/normal CRP (p = 0.0000) were related to better survival. On final multivariate analysis only CRP (p = 0.002) and DFI (p = 0.0497) were found to have an independent role in survival. When we correlated clinical and biohumoral factors, only CRP correlated with DFI (p = 0.021) and prior nephrectomy (p = 0.041). Conclusions: Our data confirm that some clinical and biohumoral factors may be strongly related to survival in metastatic renal cell carcinoma. The interesting new aspect emerging from this study is the prognostic value of CRP and fibrinogen, which are able to discriminate a good from a poor prognosis.