Polycythemia Vera: Causes, Symptoms, and Treatment

Polycythemia vera (PV) is a blood disorder where your body makes too many red blood cells. This thickens your blood, raising the risk of clots, heart attack, and stroke. It can also cause annoying symptoms like itchy skin, blurred vision, and nosebleeds. This condition mainly affects older adults and is rare, occurring in about 50 out of 100,000 people in the U.S.

Is Polycythemia vera Cancer?

PV is a type of blood cancer called myeloproliferative neoplasm (MPN). Many patients wonder, “Is polycythemia vera cancer?” The answer is yes, it results from a gene mutation, usually acquired during life, that triggers the overproduction of red blood cells. While slow-growing, PV can lead to serious complications if untreated. Early diagnosis and proper care help manage symptoms and prevent complications.

Symptoms of Polycythemia Vera

In Polycythemia vera, excess red blood cells thicken the blood, slowing its flow through small vessels. This can cause a variety of symptoms, including:

• Shortness of breath, especially when lying down
• Dizziness or lightheadedness
• Constant fatigue
• Headaches
• Fullness in the left upper abdomen from an enlarged spleen
• Swelling or pain in veins near the skin (phlebitis)
• Itchy skin, particularly after warm baths
• Reddened skin
• Vision problems or blurred vision
• Joint pain
• Ringing in the ears (tinnitus)

Causes of Polycythemia Vera

Polycythemia vera starts in the bone marrow, the soft tissue inside bones where blood cells form. The condition begins when a single stem cell develops a genetic mutation that makes it reproduce abnormally.

In more than 90% of cases, the affected gene is JAK2. This mutation tells stem cells to keep making new cells nonstop. The abnormal cells then multiply and gradually crowd out normal blood cells.

Most JAK2 mutations are acquired during life and not inherited from the family. However, rare cases show polycythemia vera appearing in multiple family members.

Complications of Polycythemia Vera

• Blood Clots: Thicker blood raises the risk of clots that may cause stroke, heart attack, DVT, or organ damage.
• Gout: Rapid red blood cell turnover increases uric acid levels, leading to gout or sometimes kidney stones.
• Progression to Other Cancers: In certain cases, PV may progress to myelofibrosis or acute leukemia.

Diagnosis of Polycythemia Vera

Doctors usually suspect polycythemia vera when routine blood tests show unusually high red blood cell counts. Because other conditions can also cause high red cells, several tests are needed to confirm PV and rule out other causes.

• Complete Blood Count (CBC): This is often the first step. It measures the number of red blood cells, white blood cells, and platelets. In PV, red blood cell levels are consistently high, and platelets or white blood cells may also be increased.
• Blood Chemistry Tests: These check for elevated uric acid (linked to gout) and other substances that suggest high blood cell turnover.
• Erythropoietin (EPO) Level: This hormone tells the body to make red blood cells. In PV, EPO levels are usually low, since the bone marrow is making cells without needing a signal.
• JAK2 Gene Mutation Test: More than 90% of people with PV have the JAK2 mutation. Detecting this mutation strongly supports the diagnosis.
• Bone Marrow Biopsy: A small sample of bone marrow is examined under a microscope. In PV, it shows abnormal stem cells and an overproduction of red blood cells, sometimes with excess white blood cells and platelets.

Doctors combine results from these tests to confirm PV. Since symptoms often overlap with other conditions, an accurate diagnosis is crucial to start treatment early and prevent complications like blood clots or organ damage.

Treatment Options for Polycythemia vera

Treatment for PV can involve several approaches, ranging from standard care to advanced therapies.

Cornerstone Treatments

1) Phlebotomy (therapeutic blood removal)

• Phlebotomy quickly lowers hematocrit (Hct) and reduces clot risk.
• Trials show keeping Hct below 45% cuts the rate of major thrombosis and cardiovascular death. For most adults, clinicians target Hct <45%.

2) Low-dose aspirin

• Unless contraindicated, low-dose aspirin reduces arterial and venous thrombotic events in PV.

These two measures form the baseline for most patients, especially those at low risk.

Cytoreductive therapies (when to use them and options)

Cytoreductive drugs lower the bone-marrow production of blood cells. Clinicians add them for high-risk patients or those with uncontrolled counts, symptomatic splenomegaly, or intolerance to repeated phlebotomy.

Hydroxyurea (HU) — the most commonly used first-line agent

Hydroxyurea is a cancer medication that works by slowing the growth of new cells in the body. In polycythemia vera (PV), it helps reduce the number of red blood cells and platelets, the blood components responsible for clotting.

Interferon-α (including long-acting, pegylated forms)

Interferon controls counts and can induce durable molecular responses in some patients.

Ruxolitinib (JAK1/2 inhibitor)

• Ruxolitinib (Jakafi) is an FDA-approved Janus kinase (JAK) 1 and 2 inhibitor used to treat polycythemia vera (PV) in patients who cannot tolerate or do not respond to hydroxyurea.
• It helps regulate hematocrit levels, shrink an enlarged spleen, and ease PV-related symptoms such as itching and fatigue.

Curative option: allogeneic hematopoietic stem-cell transplant (HSCT)

HSCT can cure PV but carries a high risk.

Doctors reserve it for younger patients who progress to myelofibrosis or acute leukemia or who have very aggressive, treatment-refractory disease.

Monitoring and follow-up

• Regular CBCs to guide phlebotomy and drug doses.
• Periodic assessment of symptoms and spleen size.
• Monitor for drug toxicity (CBC, liver tests).
• Reassess therapy if thrombotic events, intolerable side effects, or disease progression occur.

How Clinical Trials Shape the Future of Cancer Treatment

Oncology research plays a vital role in discovering new ways to prevent, diagnose, and treat different types of cancer. Clinical research studies help improve existing therapies and introduce innovative options that can improve patient outcomes.

For example, myelofibrosis clinical trials are exploring new treatment possibilities to ease symptoms, improve blood cell production, and slow disease progression. Through these studies, patients receive expert medical care, may gain access to potential therapies, and contribute to advances in cancer research.

Read More: Everything You Need To Know About Idiopathic Myelofibrosis

Conclusion:

In conclusion, polycythemia vera is a rare but serious blood cancer that requires timely diagnosis and proper management. With treatments like phlebotomy, medications, and ongoing clinical research, patients can manage symptoms, reduce risks, and improve quality of life. Early care and regular follow-up remain key to preventing severe complications.