Polycythemia Vera: Thinking Beyond the Hematocrit

Polycythemia vera is a Philadelphia chromosome-negative myeloproliferative neoplasm that results in increased myeloproliferation. It is a debilitating disease characterized by the overproduction of red blood cells, but it also can result in increased white blood cells and platelets. Patients experience a shortened overall survival due to an increased risk of thrombotic events, including stroke, myocardial infarction, pulmonary embolism, and deep vein thrombosis. Current treatment strategies in clinical practice are driven by mitigating the risk of these thrombotic events by reducing patients' hematocrit. In addition to thrombosis risk, polycythemia vera patients have constitutional symptoms such as fatigue, itching, bone pain, erythromelalgia, and splenomegaly. An increased risk of transformation of their disease to acute myeloid leukemia and/or myelofibrosis can also affect long-term survival in polycythemia vera. Additional research has identified other risk factors, such as increased white blood cells, increased platelet count, and cytokine levels, which can alter the prognosis of the disease. In this review, we will discuss the current treatment strategies in polycythemia vera and determine if incorporating additional biomarkers as endpoints is feasible in clinical practice.