From the Guidelines
The initial management of erythrocytosis, particularly polycythemia vera (PV), should focus on reducing blood viscosity and thrombotic risk through therapeutic phlebotomy and low-dose aspirin, with cytoreductive therapy indicated for high-risk patients. Therapeutic phlebotomy is the cornerstone of initial treatment, removing 450-500 mL of blood every 2-3 days until the hematocrit is below 45% for men and 42% for women, as evidenced by the European LeukemiaNet recommendations 1. This target hematocrit reduces the risk of cardiovascular events, as demonstrated by the randomized phase 3 CYTO-PV trial, which showed a significant reduction in thrombotic events in patients with a target hematocrit of less than 45% compared to those with a target hematocrit of 45-50% 1. Low-dose aspirin (81-100 mg daily) should be added unless contraindicated to decrease thrombotic complications, as supported by the European Organisation for Research and Treatment of Cancer trial, which showed a significant reduction in thrombotic events with aspirin therapy 1. Cytoreductive therapy is indicated for high-risk patients (age >60 or history of thrombosis), with hydroxyurea being the first-line agent typically started at 500-1000 mg daily and titrated to maintain hematocrit targets while keeping platelets and white blood cells within normal ranges, as recommended by the European LeukemiaNet guidelines 1. Some key points to consider in the management of erythrocytosis include:
- Maintaining adequate hydration to prevent dehydration and reduce blood viscosity
- Avoiding extreme heat exposure and minimizing activities that could increase blood viscosity
- Addressing cardiovascular risk factors like hypertension, diabetes, and smoking to reduce the risk of thrombotic events
- Regular monitoring of blood counts, symptoms, and spleen size to adjust therapy and detect disease progression, as emphasized by the Mayo Clinic Proceedings review 1. Overall, a comprehensive approach that addresses both the immediate risks of hyperviscosity and the long-term complications of this myeloproliferative neoplasm is essential for optimal management of erythrocytosis.
From the Research
Initial Management of Erythrocytosis
The initial management of erythrocytosis, particularly primary erythrocytosis such as polycythemia vera, involves several key steps:
- Therapeutic phlebotomy to reduce the risk of thrombosis, with a goal hematocrit of less than 45% 2, 3, 4
- Low-dose aspirin to prevent thrombotic events, unless contraindicated 2, 3, 4
- Cytoreductive therapy, such as hydroxyurea or interferon, for patients at high risk of thrombosis or with persistent symptoms 2, 3, 4
Diagnosis and Risk Stratification
Diagnosis of polycythemia vera is based on the presence of erythrocytosis, often with associated leukocytosis and thrombocytosis, and the presence of a JAK2 gene variant 2, 3, 5
- Risk stratification is based on factors such as age, prior thrombosis, and leukocytosis, with high-risk patients requiring more aggressive treatment 2, 3
Treatment Goals
The goal of treatment is to prevent thrombohemorrhagic complications and improve quality of life, with treatment individualized based on patient risk factors and symptoms 2, 3, 4
- Treatment may include phlebotomy, aspirin, and cytoreductive therapy, with the goal of reducing the risk of thrombosis and improving symptoms 2, 3, 4
Investigation and Diagnosis
Investigation of erythrocytosis involves measurement of erythropoietin level, mutational testing, and possibly bone marrow biopsy, to determine the underlying cause of the erythrocytosis 6