C-reactive protein is a strong predictor for anaemia in renal cell carcinoma: role of IL-6 in overall survival

Level of Evidence 4 What's known on the subject? and What does the study add? The incidence of renal cell carcinoma (RCC)-associated anaemia has been linked with more aggressive tumours. Metastatic RCC patients with elevated IL-6 levels have significantly decreased haemoglobin concentrations. We elucidate the association of progression of advanced RCC with anaemia and different factors influencing tumour-associated anaemia. Interleukin-6 emerges as a possible target to treat cancer-related anaemia in metastatic RCC. OBJECTIVE center dot To elucidate the association of progression of advanced renal cell carcinoma with anaemia and investigate factors influencing tumor-associated anaemia. PATIENTS AND METHODS center dot We analyzed different clinical variables to study associations with anaemia in 86 metastatic renal cell carcinoma patients. center dot 45 (52%) of patients had already developed anaemia prior to therapy. RESULTS center dot Anaemic patients had an increase in the serum markers C-reactive protein (CRP), IL-6 and erythropoietin (EPO). In addition we observed substantial correlation between IL-6 and CRP serum levels (R = 0.639, P < 0.0001). center dot Univariate logistic regression analysis revealed that patients with IL-6 > 10 pg/mL had a considerable increase in risk for anaemia (odds ratio 3.86, P = 0.003). center dot In addition, patients with CRP > 0.7 mg/dL had a very strong increase in risk for anaemia (OR = 14.08, P < 0.0001). center dot Stepwise multivariate logistic regression analysis confirmed CRP > 0.7 mg/mL as the only independent predictor for anaemia. Cox-regression modeling selected serum IL-6 as the strongest independent prognostic indicator (hazard ratio 3.58, P < 0.0001). CONCLUSION center dot Anaemia depends on serum IL-6, which is a strong inductor of CRP and regulator of the iron-transport. Serum IL-6 may be considered as a target to treat cancer-related anaemia.