By Julia Janzen, BS, LPN, CRC
Polycythemia Vera (PV) is a disorder of the bone marrow known as a “myeloproliferative neoplasm” (MPN). MPN’s are a group of blood cancers that share several common denominators, including the early production of blood cells. Having an MPN means that an alteration in DNA has occurred, which causes a transformation in the bone marrow. Ultimately, the cells in the bone marrow that produce the blood cells do not develop or function correctly. PV results from an overproduction of blood cells. Normally the red cells are affected, but because the mutation occurs in the early blood-forming cell, white cells and platelets can be affected as well. Other disorders considered to be MPN’s are essential thrombocythemia and myelofibrosis.
PV is commonly linked to the genetic defect JAK2 V617F mutation, called JAK2. It is believed to have a role in the onset of PV, but the cause of the disease is still being researched. It is believed that the JAK2 mutation is acquired after conception. This means that it is not inherited from a parent. PV usually develops very slowly. It is possible to have the disorder for years without detecting any signs or symptoms. Most often, PV is discovered through routine lab work. Usually a bone marrow aspiration or biopsy is done to confirm the diagnosis. This examines the bone marrow to determine if it is producing a higher amount of blood cells than normal. The JAK2 mutation can also be detected through the bone marrow.
PV occurs more often in men and is usually diagnosed between the ages of 60-65. PV is rarely found in patients under the age of 40. There are approximately 22 cases per 100,000 people. The risk for developing PV increases with age.
Signs and symptoms of this disorder are usually due to impaired oxygen delivery caused by sludging of the blood. The blood gets too thick due to the overproduction of blood cells.
Signs and symptoms include:
- Headache
- Dizziness
- Itchiness
- Excessive sweating
- Weakness
- Shortness of breath
- Numbness, tingling or burning in the hands, feet, arms, or legs
- Visual disturbances
- Ringing in the ears
- Fatigue
- Blood clots
- Bleeding
- Feeling of fullness or bloating due to enlarged spleen
- Facial plethora
- Chest pain
- Gout
With treatment, most people have few complications related to the disorder. PV is not curable, but it can be managed effectively. It is possible to have a normal quality of life. Usually daily activities and employment are not disrupted. Although there is a possibility that over time PV can advance into more serious blood cancers, for example, myelofibrosis, myelodysplastic syndrome, or acute leukemia.
The goals of treating PV are to control symptoms and decrease the risks of complications. Therapies are typically aimed at decreasing hematocrit and platelet numbers. Hematocrit is the proportion of red blood cells in a specific volume of blood, expressed as a percentage. An elevation in platelets occurs in at least 50 percent of patients diagnosed with PV. The classic treatments are phlebotomy and drug therapy. Phlebotomy is the removal of blood through the vein. This is done in the same way as donating blood. Phlebotomy is sometimes the only treatment needed. Drug therapy such as aspirin, helps to lessen the risk of blood clots. Other drugs such as myelosuppressive drugs help to suppress the marrow production of red cells and platelets, thus eliminating the need for phlebotomy.
Clinical trials are also another form of treatment for PV. Clinicaltrials.gov is a good resource when looking for any type of clinical trial.
Mid-Illinois Hematology & Oncology Associates, Ltd. is currently enrolling in an observational trial for PV. If interested please contact, Julia at 309-451-2207 or julia.janzen@mihoaonline.org.
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