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Unlike cancers of the breast, skin, or colon, to name a few, not many people have heard of myelofibrosis (MF). So if you have just been diagnosed with MF, it’s not surprising that you might have a lot of questions. It’s a good idea to learn more about what MF is and how it progresses.

What Is Myelofibrosis?

Myelofibrosis is a rare blood cancer that affects up to 18,500 people in the United States. It starts in your bone marrow, the soft spongy tissue that holds stem cells. In time, these cells become blood cells or other tissues like cartilage, fat, and bone cells. If you have MF, scar tissue starts to form in your bones. As the scar tissue grows and replaces healthy tissue, your body can’t make the blood cells it needs.

There are two types of MF, primary and secondary. Primary MF falls under an umbrella of conditions called chronic myeloproliferative neoplasms. These include other blood disorders such as:

  • Chronic myelogenous leukemia (CML)
  • Polycythemia vera
  • Essential thrombocythemia
  • Chronic neutrophilic leukemia
  • Chronic eosinophilic leukemia

People with primary MF have had no earlier problems related to their bone marrow. It’s caused by certain changes in your genes. It affects men and women equally. It most often affects people over the age of 65.

Secondary MF happens in people who have other bone marrow diseases. It causes the same type of scarring as primary MF. Secondary MF is more common than the primary type.


Diagnosing Myelofibrosis

To find out whether you have MF, your doctor will have to do some tests. They may include:

  • Blood tests: The most common ones are complete blood count (CBC) with differential, peripheral blood smears, and blood chemistry profiles. These show how many blood cells there are, their size and shape, and how many have matured. The tests also show the levels of important electrolytes, like chloride, potassium, and sodium.
  • Bone marrow tests: A sample of bone marrow is removed from the bone – usually a hip bone – with a needle. The marrow is checked to see which cells are in it and how many.
  • Molecular tests: These tests dig deeper, looking at how the cancer cells in the bone marrow or blood look. Lab techs will do several tests, including looking for abnormal changes in several molecules. They may do DNA sequencing, which lets them look for changes in your DNA, the molecule that holds your genetic information. And if you need an allogeneic stem cell transplant – a donation of stem cells – they will look at HLA typing. That’s used to match tissue between donors and recipients.

Classifying Myelofibrosis

Most cancers have a staging scale that shows how far along the cancer has progressed. This helps oncologists (cancer doctors) decide on treatments. Myelofibrosis doesn’t have stages. It has classifications instead. There have been different ways to classify the disease, but, the MIPSS70+ (Mutation-Enhanced International Prognostic Scoring System) is the one used most often now. It is more detailed than previous systems, which means it’s more accurate.

 MIPSS70+ 2.0, the latest version of the system, looks at changes on genetic markers found during molecular testing, as well as what doctors call “clinical risk factors.” These factors are what increases a person’s risk of getting a disease. They could be age, family history, or many other things.

 Myelofibrosis has five risk classifications:

  • Very low risk
  • Low risk
  • Intermediate risk (level 1 or 2)
  • High risk
  • Very high risk

 Myelofibrosis treatment according to classification

 As with other types of cancer, your treatment will depend on your MF classification.

  • Very low risk or low risk with no symptoms: You likely will not receive any treatment. Instead, you will have regular checkups and tests to see if your disease gets worse.
  • Low risk with symptoms: If you do have symptoms, but are still at low risk, your doctor may choose to still keep an eye on you or may suggest a medication that lowers the number of blood cells in your body. This is called cytoreductive treatment. The drugs recommended for this classification include hydroxyurea (Hydrea), interferon alfa (Intron A, Roferon-A, Pegasys), or ruxolitinib (Jakafi).
  •  Intermediate-1 risk: At this stage, you might be treated with pacritinib (Vonjo) or ruxolitinib. Or you might get an allogeneic stem cell transplant.
  • Intermediate-2 risk: At this point, your doctor may prescribe pacritinib, ruxolitinib, or fedratinib (Inrebic) as drug treatment. An allogeneic stem cell transplant may also be an option. In addition, you may need treatment for anemiacaused by MF. This could include blood transfusions or medications such as:
    • Danazol
    • Erythropoietin and darbepoetin
    • Lenalidomide
    • Pomalidomide
    • Prednisone
    • Thalidomide
  • High risk: Treatment for high risk is the same as intermediate-2 level.

Myelofibrosis Progression

As the disease gets worse or progresses, you may have new symptoms. These could include:

  • Bleeding in your stomach or esophagus, caused by increased blood pressure in your liver
  • Easier bleeding with a hard time stopping it, as clotting becomes harder
  • Pain in your belly area as your spleen gets bigger and tries to make up for your bone marrow not working right 
  • Signs of leukemia, which may include bleeding from your gums or nose, bone pain, getting infections often, and overall weakness, among others

 Myelofibrosis is not curable, but different things can affect how long you live and your quality of life. Some patients live for 6 years or longer after their diagnosis. Speak with your doctor to see which treatments would be best for you.

Show Sources

Photo Credit: iStock / Getty Images Plus / Getty Images


Blood Cancer Journal: “Myelofibrosis Treatment Algorithm 2018.”

Cancer Research UK: “What is myelofibrosis?”

Cleveland Clinic: “Myelofibrosis.”

Comprehensive Toxicology: “Secondary Myelofibrosis.”

Leukemia & Lymphoma Society: “Allogeneic Stem Cell Transplantation,” “Diagnosis,” “Treatment.”

Mayo Clinic: “Acute Lymphocytic Leukemia,” “Bone Marrow Biopsy and Aspiration,” “Myelofibrosis.”

MedlinePlus: “Myelofibrosis.”

Merck Manual: “Myelofibrosis.”

Mount Sinai: “Myelofibrosis.”

National Cancer Institute: “Bone marrow,” “Chronic myeloproliferative neoplasm,” “DNA,” “Risk factor.”

Rare Disease Advisor: “Myelofibrosis.”

Weill Cornell Medicine, Richard T. Silver MD Myeloproliferative Neoplasms Center: “Myelofibrosis.”