Erythropoiesis stimulating agents, thrombosis and cancer

Venous thromboembolism (VTE) is common in cancer and is associated with both morbidity and mortality. Erythropoiesis stimulating agents (ESAs) were originally developed to correct anemia. Recent trials in cancer patients however, raise concerns over both increased VTE rates and the possibility of worse tumour outcomes and increased mortality with ESA use. The most common reason offered for explaining the possible negative impact of ESAs on cancer outcomes has been the stimulation of erythropoietin receptors on tumour cells. Despite an extensive literature, it is unlikely that most practicing appreciate the intricate relationship and interaction between the coagulation pathways, angiogenesis and tumour progression and ESA effects. This paper will review these connections and interactions and examine the hypothesis that other mechanisms may underlie the possible negative impact of ESAs on cancer outcomes.