Polycythemia vera (PV) is a rare type of blood cancer. PV is one of the 3 most common myeloproliferative neoplasms (MPNs). PV occurs when the body makes too many red blood cells. Red blood cells are responsible for carrying oxygen through the body. Too many can cause the blood to become thicker and move more slowly. People with PV sometimes have too many white blood cells and platelets as well.
The causes of PV are largely unknown. It occurs more often in people over 60, and slightly more often in men. In very rare instances, it runs in families. Most people with this disease have an abnormal change in the JAK2 gene. Other genes may be involved as well.
Signs & Symptoms
The increase in red blood cells can cause the blood to thicken and clot, causing signs and symptoms of polycythemia vera. In early stages, patients may have few symptoms. As the disease progresses, the following symptoms may appear:
- Blood clot
- Excessive sweating
- Blurred vision or blind spots
- Itchiness, especially after a warm shower or bath
- Redness or a purplish appearance of skin
- Peptic ulcers
- Bloating or a feeling of fullness due to an enlarged spleen
- Congestive heart failure or angina
- Gout/inflammation of joints
Diagnosis & Treatment Planning
Blood tests are used to diagnose polycythemia vera. Signs may include:
- An increase in red blood cells, platelets and white bloods cells
- A high hematocrit (the proportion of red blood cells in the blood)
- An increase in hemoglobin concentration (a protein found in red blood cells)
- Low levels of erythropoietin (a hormone that controls red blood cell production)
Additional tests may include:
- Bone marrow biopsy or aspiration to take a sample of bone marrow
- Testing for the presence of JAK2 mutation or other genetic mutations
Treatment Options & Side Effects
Different healthcare providers involved in your care may include a hematologist/oncologist, a nurse, a nurse navigator, an oncology social worker, or a pharmacist. These people can help you find information and resources that may be useful before, during, and after treatment. Ask your doctor about the other members of your healthcare team, their names, and how you can arrange to meet them. You also may want to ask your insurance company to assign you a case manager to help you understand which treatments and services your health insurance will cover.
Treatment choices depend on your diagnosis and the extent of the disease. The various drugs used to treat polycythemia vera work in different ways, and may have different side effects. Ask for more information before starting treatment. Your options may include:
Aspirin, taken orally in low doses, can help reduce the risk of clotting, and is recommended for most PV patients
Phlebotomy removes blood from a vein in order to lower the number of red blood cells in the body. This treatment is often used first.
Cytoreductive therapies (e.g. hydroxyurea), which may reduce the blood counts, are usually given by mouth (orally).
Inteferon alfa, which can lower blood counts, is given subcutaneously. Sustained release preparations (e.g. peginterferon alfa-2a), have superior tolerability.
JAK inhibitors are new kinds of drugs that focus on targeting a genetic problem that has been linked to polycythemia vera.