Polycythemia vera

Medical condition

Polycythemia vera
Other names	Polycythaemia vera (PV, PCV), erythremia, primary polycythemia, Vaquez disease, Osler-Vaquez disease, polycythemia rubra vera[1]
Blood smear from a patient with polycythemia vera
Specialty	Oncology, hematology

In

People with polycythemia vera can be asymptomatic.^[4] Clinical symptoms of polycythemia vera are mostly due to hyperviscosity of blood. A classic symptom of polycythemia vera is pruritus or itching, particularly after exposure to warm water (such as when taking a bath),^[5] which may be due to abnormal histamine release^[6][7] or prostaglandin production.^[8] Such itching is present in approximately 40% of patients with polycythemia vera.^[9] Gouty arthritis may be present in up to 20% of patients.^[9] Peptic ulcer disease is also common in patients with polycythemia vera; most likely due to increased histamine from mast cells, but may be related to an increased susceptibility to infection with the ulcer-causing bacterium H. pylori.^[10]

A classic symptom of polycythemia vera (and the related myeloproliferative disease

Diagnostic criteria for polycythemia vera were modified by the World Health Organisation in 2016.[16] The WHO criteria for polycythemia vera are specifically outlined in Table 4, and emphasis is given to accurate histological observations as proven predictors in the prognosis of the disease.

As summarized by Verstovek following the 2016 European Hematology Association Congress,^[17] there are 3 major criteria for PV diagnosis:

1. The first is a very high red blood cell count, which is usually identified by elevated levels of hemoglobin or hematocrit;
2. A bone marrow biopsy that shows hypercellularity and abnormalities in megakaryocytes; and
3. The presence of a mutation in the Janus kinase 2 (JAK2) gene.

Patients usually have a very low level of erythropoietin, a growth factor that increases the production of red blood cells, which may be considered a minor diagnostic feature.

A mutation in the

Untreated, polycythemia vera can be fatal, with the median survival in patients being 1.5-3 years.[26]^[27][28] Data on the effect of life-span of an individual with treated polycythemia vera is inconclusive due to the rarity of the disease. Studies show the median survival rate of controlled Polycythemia Vera ranges from 10 to 20 years; however, most observations are of people diagnosed in their 60s. Patients live close to a normal life expectancy.^[29]

Frequent blood withdrawals (phlebotomy) are one form of treatment, which often may be combined with other therapies. The removal of blood from the body induces iron deficiency, thereby decreasing the hemoglobin / hematocrit level, and reducing the risk of blood clots. Phlebotomy is typically performed to bring their hematocrit (red blood cell percentage) down below 45 for men or 42 for women.^[30] It has been observed that phlebotomy also reduces cognitive impairment.^[31]

Medications are also used which reduce the number of red blood cells. These include hydroxyurea and interferon therapy, among others.^[32] The tendency of some practitioners to avoid chemotherapy if possible, especially in young patients, is a result of research indicating possible increased risk of transformation to acute myelogenous leukemia (AML). While hydroxyurea is considered a safer chemotherapy in this aspect, there is still some debate about its long-term safety.^[33]

There are indications that the lung cancer drug erlotinib may be an additional treatment option for those with certain genetic markers.^[34]

Ruxolitinib (brand name Jakafi), a Janus kinase 2 (JAK2) inhibitor, is also used to treat polycythemia.^[35]

Ropeginterferon alfa-2b (Besremi) was approved for medical use in the European Union in February 2019,^[36] and in the United States in November 2021.^[37][38] Ropeginterferon alfa-2b is the first medication approved by the U.S. Food and Drug Administration (FDA) to treat polycythemia vera that people can take regardless of their treatment history, and the first interferon therapy specifically approved for polycythemia vera.^[37] Interferon alfa-2b is also used.^[32]

Epidemiology

Polycythemia vera occurs in all age groups,^[39] although the incidence increases with age. One study found the median age at diagnosis to be 60 years,^[9] while a Mayo Clinic study in Olmsted County, Minnesota found that the highest incidence was in people aged 70–79 years.^[40] The overall incidence in the Minnesota population was 1.9 per 100,000 person-years, and the disease was more common in men than women.^[40] A cluster around a toxic site was confirmed in northeast Pennsylvania in 2008.^[41]

Notable deaths

• First Lady of Kentucky^[42]
• Ron Miles (1963–2022), American jazz trumpeter^[43]
• Nell Rankin (1924–2005), American mezzo-soprano^[44]

References