If you have polycythemia vera, it means you have a slow-growing blood cancer that can sometimes turn into another, more serious blood cancer. There's no cure, but treatments can help control your symptoms and may lower the chances that it will turn into a disease such as myelofibrosis, myelodysplastic syndrome, or acute myeloid leukemia.
How Does Polycythemia Vera Advance?
Polycythemia vera affects your bone marrow, the spongy tissue in the center of your bones that makes blood cells. The disease causes your bone marrow to make too many blood cells, which can lead to health problems like sluggish circulation and blood clots.
Polycythemia vera is caused by a genetic change (called a mutation) to your stem cells, which are cells that grow into other types of cells in your body. In this case, the stem cells that have genetic changes are the ones that grow into red blood cells, white blood cells, and platelets. The mutation causes them to divide and grow out of control.
These out-of-control stem cells start to crowd your bone marrow. When they break down, scar tissue forms, which over time damages your bone marrow. This is called the "spent phase."
Research suggests polycythemia vera turns into another blood cancer in less than 20% of cases. It usually happens during the later stages of the disease.
Polycythemia vera treatments help reduce your risk of symptoms and complications. But for some people, the disease still gets worse and turns into another blood cancer, despite treatment.
How Do You Know if Your Disease Is Changing?
Because polycythemia vera grows slowly, you may not realize that it has turned into another disease. What's more, many symptoms of other blood cancers are the same as polycythemia vera. They include:
- Tiredness, weakness, and shortness of breath
- Easy bleeding and bruising
- Fever
- Bone or joint pain and swelling
See your doctor if you notice any changes in your symptoms or new health problems.
As part of the care of your cancer, you'll get regular checkups and blood tests. Your doctor can watch for changes, such as those to your spleen or blood cell count, that may be signs of another condition.
To diagnose a new blood cancer, your doctor will order more tests. They may include:
- Blood tests
- Gene tests
- Bone marrow tests
Myelofibrosis
About 10% to 15% of the time, polycythemia vera changes into myelofibrosis. This is called post-polycythemia vera myelofibrosis.
Myelofibrosis is a blood cancer where your bone marrow has so much scar tissue that it can't make enough healthy blood cells. It causes anemia, a condition where your body doesn't have enough red blood cells. It also leads to a large spleen and liver.
Most of the time, myelofibrosis treatments focus on easing your anemia and enlarged spleen. If your disease is slow-growing, you may not need treatment right away.
Anemia treatments include:
- Androgen therapy. A synthetic version of the male hormone androgen can boost red blood cell counts.
- Immunomodulators. These drugs help your immune system work, which can lessen anemia.
- Blood transfusions. You'll receive healthy blood through an IV.
Treatments for an enlarged spleen include:
- Targeted drug therapy. They may target a certain enzyme involved in myelofibrosis.
- Chemotherapy. These chemicals kill cancer cells and shrink the spleen.
- Radiation therapy. High-powered rays destroy cells, which can reduce spleen size.
- Surgery to remove the spleen. This is an option if other treatments don't work.
In rare cases, doctors treat myelofibrosis with stem cell transplants. In this procedure, you get chemotherapy or radiation therapy to kill your stem cells. You'll get healthy stem cells from a donor through an IV.
Myelodysplastic Syndrome
If your polycythemia vera turns into myelodysplastic syndrome (MDS), you now have one of a group of conditions where stem cells in the bone marrow don't work right. They make abnormal blood cells that die earlier than usual. As a result, you may not have enough blood cells in your body. This can set the stage for anemia and other health problems.
You could have also MDS and myelofibrosis at the same time.
MDS treatments can lessen symptoms such as fatigue. They might also help keep the disease from getting worse. For example, it's possible it can turn into acute myeloid leukemia (AML). One in three people with MDS will get AML, but some treatments may lower the chances.
Treatments for MDS include:
- Blood transfusions
- Growth factors, which are drugs that help you make more red blood cells, white blood cells, or platelets
- Chemotherapy, which kills cancer cells, including the abnormal stem cells that play a role in MDS
- Drugs that affect the immune system, which may help certain types of MDS
- Stem cell transplant
Acute Myeloid Leukemia
One study shows that anywhere from 2% to 14% of the time, polycythemia vera changes into AML within 10 years. In this disease, stem cells in your bone marrow turn into unhealthy blood cells, including white blood cells called myeloblasts. These cells grow out of control, crowding out healthy blood cells.
Your doctor may suggest treatments such as:
- Chemotherapy
- Targeted treatments that work against certain parts of the cancer cells. One medicine targets an enzyme within them, causing them to die.
- Stem cell transplant