What is polycythemia vera?
Polycythemia vera (PV) is a chronic blood cancer in which the bone marrow makes too many red blood cells, and sometimes too many white blood cells and platelets. This extra production makes the blood “thicker,” which can slow blood flow and raise the risk of blood clots.
PV is part of a group of conditions called myeloproliferative neoplasms (MPNs), which also include essential thrombocythemia and myelofibrosis. It usually develops slowly over many years, and treatment focuses on lowering clot risk, controlling blood counts, and managing symptoms.
How is PV diagnosed?
PV is often found when a routine blood test shows a high hemoglobin, hematocrit, or red blood cell count. Your doctor will repeat blood tests and look for other clues, such as high platelets or white blood cells, low erythropoietin (EPO) levels, and iron status.
A bone marrow biopsy may be done to confirm the diagnosis and look at how the marrow cells are growing. Most people with PV have a mutation in the JAK2 gene, which a blood test can detect and which helps confirm PV as an MPN.
What symptoms should I watch for?
Some people with PV feel well at diagnosis, while others notice symptoms that have slowly developed over time. Common symptoms include headache, dizziness, blurred vision, ringing in the ears, fatigue, shortness of breath, and a reddish or “plethoric” face.
Other frequent issues are itching (especially after a warm bath or shower), burning pain or redness in the hands and feet, night sweats, and a feeling of fullness or discomfort under the left ribs from an enlarged spleen. You should also report any unusual bleeding, new chest pain, trouble breathing, or sudden leg swelling, which can be signs of a blood clot.
How serious is PV?
PV is a serious condition because it increases the risk of blood clots, which can cause heart attack, stroke, or clots in the veins. However, with careful management, many people with PV live for decades and maintain a good quality of life.
Your outlook depends on your age, overall health, blood counts, presence of symptoms, and whether you have had clots before. Modern treatments, including phlebotomy, aspirin, interferon, and JAK inhibitors, have improved survival and lowered complication rates over time.
What are the main risks and complications of PV?
The biggest concern in PV is blood clots in arteries or veins, which can cause stroke, heart attack, or clots in the legs, lungs, or abdominal veins. Other possible complications include bleeding, very high blood counts, painful redness in hands and feet, or a very enlarged spleen.
Over many years, a small percentage of people with PV may develop myelofibrosis (a related bone marrow scarring condition) or acute myeloid leukemia, which are more aggressive diseases. Regular follow‑up helps your team detect and address complications as early as possible.
How do doctors decide my risk level?
Doctors usually divide PV into lower‑risk and higher‑risk groups to guide treatment. Key factors include your age (often with age 60 as a cutoff), whether you have had a blood clot before, your blood counts, symptoms, and other health issues such as high blood pressure, diabetes, or smoking.
These risk levels help decide whether phlebotomy and aspirin alone are enough or whether you also need medicines to lower blood counts (cytoreductive therapy). Even if you are considered lower‑risk, your plan can change over time if your situation changes.
What treatments are available for PV?
The goals of PV treatment are to reduce clot risk, control symptoms, and prevent disease progression. Common treatments include:
Phlebotomy: Regularly removing blood to keep your hematocrit (the percentage of blood made up of red blood cells) below about 45%, which lowers clot risk.
Low‑dose aspirin: Helps make platelets less “sticky” and reduces clot risk and symptoms like burning in hands and feet, when safe for you.
Cytoreductive therapy: Medicines that lower blood counts, such as hydroxyurea or interferon (including ropeginterferon alfa), for people at higher risk or who cannot be controlled with phlebotomy and aspirin alone.
JAK inhibitors: Ruxolitinib and other JAK‑targeted drugs may be used in people who do not tolerate or respond well to hydroxyurea, or who have significant symptoms or spleen enlargement.
Your doctor will tailor your plan to your specific risk factors, symptoms, and preferences.
What is phlebotomy and why is it important?
Phlebotomy is a procedure similar to donating blood, where a set amount of blood is removed through a needle in your vein. This lowers the number of red blood cells and makes the blood less thick, which helps reduce the risk of clots.
At first, you may need phlebotomies more often to bring your hematocrit down; later, they may be spaced out to maintain your target level. Many guidelines recommend keeping hematocrit below about 45% to best reduce clot risk.
What are interferon and ropeginterferon, and when are they used?
Interferon is a medicine that can reduce blood counts and may help control the underlying disease in PV. Ropeginterferon alfa‑2b is a newer, long‑acting form that is given by injection and is now recommended in guidelines as a preferred first‑line cytoreductive therapy for many adults with symptomatic PV.
These medicines may be especially considered in younger patients, people who cannot tolerate hydroxyurea, or those who want a drug that may have more “disease‑modifying” effects. Side effects can include flu‑like symptoms, mood changes, and effects on the liver or thyroid, so close monitoring is important.
What is Jakafi (ruxolitinib), and how does it work in PV?
Jakafi (ruxolitinib) is an oral JAK1/JAK2 inhibitor that helps block overactive JAK‑STAT signaling, a key pathway that drives abnormal blood cell production and inflammation in PV and other MPNs. By targeting this pathway, Jakafi can lower blood counts, shrink an enlarged spleen, and improve PV‑related symptoms such as itching, night sweats, and fatigue.
In clinical studies, many patients treated with ruxolitinib achieved better control of hematocrit without phlebotomy and had reductions in spleen volume compared with standard therapies. Patients also reported improvements in quality of life and symptom burden.
When is Jakafi typically used for polycythemia vera?
In the United States, Jakafi is approved for adults with PV who have had an inadequate response to or are intolerant of hydroxyurea, a commonly used cytoreductive medicine. This means it is usually considered after trying hydroxyurea, particularly in higher‑risk patients or those needing cytoreduction.
Guidelines and real‑world data support using ruxolitinib when patients continue to need frequent phlebotomies, have uncontrolled blood counts, have an enlarged spleen that does not shrink, or experience unacceptable side effects on hydroxyurea. Your doctor may discuss Jakafi if your PV remains active despite standard care or if you do not tolerate other medicines well.
Why might my doctor recommend switching to Jakafi?
Your doctor might recommend Jakafi if you are still needing repeated phlebotomies, your hematocrit or white blood cell counts stay high, or your spleen remains enlarged despite hydroxyurea. Other reasons include persistent or severe PV symptoms (such as troublesome itching, night sweats, or early fullness) or side effects from hydroxyurea that are difficult to manage.
Studies show that patients who switch from hydroxyurea to ruxolitinib often achieve better hematocrit and white blood cell control and need fewer phlebotomies. Many also report improvement in spleen‑related symptoms and overall quality of life.
What side effects should I know about with Jakafi?
The most common side effects of Jakafi in PV include low red blood cell and platelet counts (anemia and thrombocytopenia), bruising, dizziness, headache, and diarrhea. Because it can lower blood counts, your doctor will check your labs regularly and may adjust your dose, pause treatment, or use supportive measures if needed.
Serious but less common risks that have been seen with JAK inhibitors include infections and blood clots, so you should tell your healthcare team right away if you develop fevers, chills, new pain or swelling in a leg, sudden chest pain, or trouble breathing. Your doctor will review your individual risks and benefits before starting Jakafi and will monitor you closely during treatment.
How often will I need labs and follow‑up if I’m on Jakafi?
When you start Jakafi, you will typically have blood tests more frequently to monitor your blood counts and adjust the dose safely. Once a stable dose is reached and your counts are controlled, lab checks may become less frequent but remain an important part of your routine care.
At each visit, your doctor will also ask about symptoms, check your spleen, and review any side effects or new health issues. Keeping all scheduled appointments and labs is key to getting the most benefit from Jakafi while minimizing risks.
What side effects should I know about from other PV treatments?
Phlebotomy can cause temporary lightheadedness, fatigue, or low iron levels, but is generally well tolerated when monitored. Aspirin can irritate the stomach and increase the risk of bleeding, particularly in people with ulcers or other bleeding risks.
Hydroxyurea may cause low blood counts, mouth sores, or skin and nail changes. Interferon and ropeginterferon can cause flu‑like symptoms, injection‑site reactions, mood changes, or autoimmune effects. Your care team will monitor you regularly and adjust treatment if side effects become a problem.
How often will I need blood tests and doctor visits?
Because PV is a lifelong condition, regular monitoring is essential. Early on or when changing treatment, you may have visits and blood tests more often; once things are stable, many people are seen every few months.
At each visit, your doctor will review your symptoms, check your blood pressure and spleen size, and order lab tests to look at your hematocrit, hemoglobin, platelets, and other values. Sticking to your appointment and lab schedule helps keep your hematocrit on target and lowers complications.
Can lifestyle changes help manage PV?
Lifestyle changes are an important part of PV care and work together with medical treatment. Helpful steps include not smoking, staying physically active as you are able, maintaining a healthy weight, and following a heart‑healthy diet with fruits, vegetables, whole grains, and lean proteins.
Staying well hydrated can help keep your blood from becoming too concentrated, especially during hot weather, illness, or long travel. Managing blood pressure, cholesterol, and diabetes, and limiting long periods of sitting without moving your legs, can also reduce clot risk.
How might PV affect surgery, dental work, or other procedures?
Because PV increases clot and sometimes bleeding risk, it is important to tell surgeons, dentists, and other healthcare providers about your diagnosis and treatments before any procedure. Your hematologist may adjust your phlebotomy schedule, aspirin, or cytoreductive medicines around the time of surgery.
You may need additional blood tests or, in some cases, short‑term changes in blood‑thinning medicines to balance bleeding and clotting risks. Ask your hematologist if you should carry a wallet card or summary describing your PV and current treatment plan.
Should I consider joining a clinical trial?
Clinical trials look at new treatments or new ways to use existing therapies in PV and may offer access to options not yet widely available. Studies are exploring improved interferons, new targeted drugs, and combination approaches aimed at better controlling the disease and preventing progression.
Not everyone needs or wants a clinical trial, but it can be useful to ask your hematologist whether a study might fit your situation now or in the future. Major cancer centers, MPN advocacy groups, and trial registries can be good places to learn about open PV studies.
How can I cope emotionally with a PV diagnosis?
Being told you have a chronic blood cancer can cause worry, sadness, or frustration, even when your disease is well controlled. Many people find it helpful to learn about PV from reliable sources, bring written questions to visits, and include a family member or friend in important appointments.
Support groups (online or in person), counseling, and patient communities for people with PV or other MPNs can provide understanding and practical tips. Let your care team know if you feel overwhelmed or depressed; they can connect you with social workers, mental health professionals, or peer mentors who understand what you are going through.
Where can I find reliable information and support?
There are many trustworthy resources for people living with PV, including national cancer organizations, MPN patient groups, and pharmaceutical patient‑education programs. These organizations offer booklets, videos, visit planners, symptom trackers, and events where you can hear from experts and other patients.
Join the conversation on CancerConnect to share your experience, ask a question and connect with others living with MF. CancerConnect has been supporting, empowering, and connecting patients and caregivers since 1997. CancerConnect combines a moderated community, daily cancer news, and educational resources.
This “Ask the Expert” FAQ is for education only and is not a substitute for medical advice. Always discuss your own situation, test results, and treatment options with your healthcare team.
More Reading
Overview of Myeloproliferative Neoplasms
Myeloproliferative Neoplasms and Fatigue
Depression Is Not “Just in Your Head”: Spotting and Treating Hidden Mood Changes in MPNs
