Polycythemia vera: description & prognosis

Brief overview:

  • What is polycythaemia vera? Rare disease of the hematopoietic cells of the bone marrow, form of blood cancer.
  • Prognosis: Untreated, prognosis is unfavorable; with treatment, median survival is 14 to 19 years.
  • Treatment: phlebotomy, medications (blood thinners, cytostatics, interferon-alpha, JAK inhibitors), bone marrow transplant, prevention of thrombosis
  • Symptoms: Fatigue, night sweats, itching, bone pain, weight loss, thrombosis.
  • Causes: Acquired gene alteration (mutation).
  • Risk factors: Older age, thrombosis already suffered
  • Diagnosis: Blood test, molecular genetic test for a gene mutation, bone marrow biopsy, ultrasound
  • Prevention: Healthy lifestyle, examination for gene mutation in case of familial clustering

What is PV?

The term polycythemia (also: polycythemia) basically refers to an increase in the number of red blood cells (erythrocytes), hematocrit (proportion of solid blood components) and hemoglobin (red blood pigment). Depending on the cause, a distinction is made between different forms of polycythemia:

  • Primary polycythemia: polycythaemia vera (PV)
  • Secondary polycythemia: due to increased formation of erythropoietin (hormone that promotes the formation of red blood cells in the bone marrow, erythropoiesis)
  • Relative polycythemia: due to a lack of fluid in the body, such as in cases of severe vomiting

In PV, red and white blood cells in particular multiply uncontrollably, and to a lesser extent platelets. A special form of PV is polycythaemia vera rubra, in which only the red blood cells multiply. However, it occurs much less frequently than PV.

Course of PV

PV progresses insidiously and in many cases does not cause any symptoms at the beginning. Two phases of the disease can be distinguished:

Chronic phase (polycythemic phase): Increased red blood cell production may continue unnoticed for up to 20 years.

Progressive late phase (Spent phase): In up to 25 percent of patients, “secondary myelofibrosis” develops from PV. Blood formation then no longer takes place in the bone marrow, but in the spleen or liver. In about ten percent of cases, PV progresses to myelodysplasia (myelodysplastic syndrome, MDS) or acute myeloid leukemia (AML).

Frequency

PV is a rare disease: between 0.4 and 2.8 percent of the population in Europe are affected each year, men slightly more frequently than women. At the time of diagnosis, those affected are on average between 60 and 65 years old.

PV and severe disability

Information as well as applications for the determination of severe disability can be obtained from the respective municipal or city administration as well as from health offices!

What is my life expectancy with PV?

The prognosis for PV varies from case to case. Untreated, survival is very short, averaging 1.5 years. Patients who are treated have a much better life expectancy, averaging 14 to 19 years. The prevention of vascular occlusion (thromboembolism) and myelofibrosis, as well as acute leukemia, which are considered the most common causes of death, are of particular importance here.

How is PV treated?

It is essential for the treatment that the patient attends regular check-ups with the doctor. The doctor repeatedly takes blood samples and adjusts the treatment to the patient’s situation. Therefore, it is common for the doctor to modify the current therapy several times.

Reducing the risk of thrombosis

General measures to reduce the risk of blood clots are:

  • Weight normalization
  • Regular exercise
  • Sufficient fluid intake
  • Avoiding prolonged sitting
  • Treatment of existing cardiovascular diseases
  • Wearing compression stockings during long (air) trips

Lowering the hematocrit

As an alternative to bloodletting, the physician applies a so-called “erythrocytapheresis”. This procedure is similar to dialysis (blood washing for kidney disease): However, the blood is cleared of red blood cells (erythrocytes) rather than toxins.

Medication

  • Anticoagulants (platelet aggregation inhibitors) such as acetylsalicylic acid prevent platelets from clumping together and forming blood clots.
  • So-called cytostatics (cytotoxins) reduce the greatly increased cell counts by inhibiting the formation of new blood cells in the bone marrow. Alternatively, hormone-like messengers such as interferon-alpha can be used.
  • According to the latest findings, so-called JAK inhibitors are particularly suitable for the therapy of PV. They inhibit the activity of certain substances that ensure that too many blood cells are formed.

Stem cell transplantation

After the transplant, the patient receives medication to prevent the new immune system, which was also transmitted by the donor, from attacking the recipient’s body. During this time, the patient is particularly susceptible to infections. It takes about six months for the new immune system to adapt to the body. Once this phase is well overcome, the restrictions in the life of the affected person usually gradually disappear.

What can you do yourself?

These tips help to alleviate the typical complaints associated with PV:

Fatigue: Most PV patients suffer from severe exhaustion and tiredness (fatigue). It cannot be prevented, but it can be “managed” in some circumstances: Pay attention to when you feel particularly tired. Plan your activities so that they fall at a time when you usually feel at your best. Physical activity also counteracts fatigue and improves your sleep.

Night sweats: Light and loose-fitting clothes and cotton bedding will make you sweat less. Keep a towel and a glass of water handy, and try not to eat anything heavy before going to bed.

Nutrition: Nutrition plays an important role, especially in chronic diseases. Only when energy and nutrient needs are met will physical and mental functions be maintained. There is no special diet to favorably influence PV.

If there are no intolerances or allergies, a diet that is also beneficial for healthy people is advisable. Mediterranean diet is recommended, which is considered good and balanced in its composition, as it uses a lot of vegetables, fish and high-quality vegetable oils instead of animal fats.

General recommendations for a balanced diet:

  • Eat a varied diet, especially a plant-based diet.
  • Give preference to whole-grain products, especially bread, pasta, rice and flour.
  • Eat animal foods only in small quantities: fish once or twice, meat no more than 300 to 600 g per week.
  • Avoid hidden fats, prefer vegetable oils such as canola or olive oil.
  • Use salt and sugar very sparingly.
  • Drink enough water – around 1.5 liters per day.
  • Avoid sugary and alcoholic beverages.
  • Prepare your meals gently – cook food as long as necessary and as short as possible.
  • Take time to eat.
  • Watch your weight, and keep moving.

Symptoms

The disease always begins insidiously, with symptoms progressing slowly. Signs of PV may include:

  • Tiredness, fatigue
  • Reddened facial skin, blue-red skin and mucous membranes, high blood pressure (caused by the “thickened” blood)
  • Itching, especially when the skin is moistened with water (affects 70 percent of patients)
  • Night sweats and excessive daytime sweating
  • Bone pain
  • Weight loss that is neither intentional nor due to other diseases
  • Abdominal pain (diffuse pain in the right upper abdomen) and bloating due to enlargement of the spleen (splenomegaly). Because of the increased cell production, the spleen must break down a particularly large number of old and altered blood cells. In addition, in a later phase of the disease, the formation of blood cells shifts to the spleen.
  • Circulatory disturbances in the hands and feet, visual disturbances, insensitivity or tingling in the arms and legs (caused by occlusions in smaller blood vessels).

What are the causes of PV?

The cause of PV is a dysfunction of the hematopoietic cells in the bone marrow. This is triggered by a gene change (mutation) that is detectable in almost all patients with polycythaemia vera.

97 percent of all PV patients have a mutation in the so-called JAK gene (abbreviation for “Janus kinase 2”). This mutation causes the hematopoietic cells to multiply uncontrollably. Too many blood cells are formed, especially red and white blood cells. Platelets may also be produced excessively and “thicken” the blood. The result is an increased risk of thrombosis.

Even though PV occurs more frequently in some families, it is not a classic hereditary disease: the genetic mutation is not passed on, but develops in the course of life. How it comes about is unknown.

What does the doctor do?

If these blood values are elevated, the general practitioner usually refers the patient to a physician who specializes in blood disorders (hematologist) for further clarification.

The hematologist makes the diagnosis of PV on the basis of three criteria:

Blood values: elevated values of hematopoietic cells and hematocrit are typical for PV. The normal value of the hematocrit is 37 to 45 percent in women and 40 to 52 percent in men. At the time of diagnosis, PV patients often have values above 60 percent.

JAK2 mutation: Molecular genetic methods are used to examine the blood for gene changes (mutations).

Special bone marrow tests: In order to examine the bone marrow for typical changes, the physician removes a small amount of bone marrow from the patient under local or short anesthesia.

Prevention

Since the cause of the disease-causing gene mutation is unknown, there are no recommendations to prevent PV. If polycythaemia vera occurs frequently in a family, human genetic counseling is recommended. This involves a specially trained physician performing a blood test to determine whether someone carries the mutation of the JAK gene.

If the corresponding gene mutation is found, this does not necessarily mean that PV will actually break out!

Author & source information

This text corresponds to the requirements of medical literature, medical guidelines and current studies and has been reviewed by medical experts.