How Is Polycythemia Vera Staged And Classified?

Polycythemia vera (PV) is a chronic blood cancer that stays in the bone marrow and bloodstream. Unlike many cancers, which are staged based on tumor size and spread, PV is not staged in the traditional sense; instead, it is classified based on specific biological and clinical features.

Doctors focus on diagnostic criteria, risk levels for complications, and how PV progresses over time. This approach helps guide treatment decisions and monitor for changes in the disease.

The World Health Organization (WHO) has established diagnostic criteria for PV, which include both major and minor criteria. PV is diagnosed if either all three major criteria or the first two major criteria and one minor criteria are present.

• Major criteria include an elevated red blood cell mass, the presence of a JAK2 mutation, and subnormal serum erythropoietin levels (the amount of a hormone called erythropoietin, in the blood) .
• Minor criteria include bone marrow biopsy showing hypercellularity (an abnormal amount of cells) and endogenous erythroid colony formation (the hormones that stimulate red blood cell production).

Keep reading, how is polycythemia vera diagnosed? 

Phases of polycythemia vera

Polycythemia Vera generally progresses through three phases:

1. Proliferative Phase: This is the initial phase of PV, characterized by an increase in red blood cells, white blood cells, and platelets. Symptoms may include headaches, dizziness, and a feeling of fullness in the stomach due to an enlarged spleen. Many patients are diagnosed in this phase.
2. Stable Phase: In this phase, the disease is controlled with treatment. Blood counts may return to normal and symptoms may decrease.
3. Spent Phase (Post-PV Myelofibrosis): This is the final phase of PV, which occurs in a small number of patients. The bone marrow becomes scarred and can no longer produce enough blood cells, leading to anemia. This phase is also associated with an increased risk of acute leukemia.

It's important to note that not all patients with PV will progress through all three phases. The course of the disease can vary widely from person to person, and treatment can often control the disease for many years.

Risk classification: who is at higher risk for complications?

PV is also informally risk-stratified based on the chance of developing blood clots or other complications. This is not staging but helps guide treatment:

• Low-risk: Under age 60 and no history of blood clots
• High-risk: Age 60 or older and/or a history of blood clots

This risk level determines if you need more than just phlebotomy and aspirin, such as cytoreductive therapy to lower blood counts

Stay up to date with the latest polycythemia vera news

Discover breaking research, treatment updates, patient stories, and educational events tailored for the MPN community.

Read PV News