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Since 2010, myelofibrosis (MF) has been considered a form of cancer. It is one of the 3 most common myeloproliferative neoplasms (MPN) — rare blood diseases that develop when the bone marrow makes too many blood cells. In myelofibrosis, scar tissue forms inside the bone marrow. Primary myelofibrosis develops on its own. Secondary myelofibrosis can result from another bone marrow disorder (such as polycythemia vera or essential thrombocythemia). In either case, the body is not able to produce blood cells normally.

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Risk Factors

Little is known about the causes of primary myelofibrosis. It occurs in both men and women. It is usually diagnosed in people over age 50 but can affect people of any age. Doctors who study myelofibrosis in a laboratory have found that many people with the disease have a mutation (or change) in certain genes, including JAK2, CALR, or MPL.


Signs & Symptoms

Myelofibrosis often develops slowly. Symptoms may not be seen in the very early stages. The first signs are usually due to an enlarged spleen or related to abnormal blood counts. As cancer develops, your normal blood cells do not function correctly and symptoms appear. Check with your doctor if you are experiencing:

  • Fatigue, weakness, or shortness of breath. These symptoms are associated with a decrease in the red blood cells (anemia)
  • Pain or fullness below the ribs on the left side, as a result of an enlarged spleen
  • Poor appetite
  • Enlarged liver
  • Pale skin
  • Easy bruising or bleeding
  • Flat, red, pinpoint spots under the skin caused by bleeding
  • Excessive night sweats
  • Fever
  • Frequent infections, due to a low white blood cell count
  • Bone or joint pain
  • Weight loss
  • Itchiness

Diagnosis & Treatment Planning

Common first symptoms include an enlarged spleen or abnormal blood count, which prompts further evaluation. The results of a blood test that suggest a diagnosis of MF often include:

  • A decrease in the number of red blood cells (anemia) below the normal range
  • An increase or decrease in the number of white blood cells
  • An increase in platelets above the normal range (occurs in about one-third of MF patients)
  • A mild to moderate decrease in platelets below the normal range (occurs in about one-third of MF patients) 

If you have symptoms, you may be referred to a doctor who specializes in blood cancers for further testing of the blood and bone marrow, including:

Complete blood count: a blood test that measures the white blood cells, red blood cells, and platelets in the blood 

Ultrasound: uses high-frequency sound waves to look at organs and structures inside the body (including the spleen)

MRI: a scan that uses magnets and radio frequency waves to produce images of the inside of the body

Bone marrow examination: removal of a small amount of your bone and bone marrow for laboratory analysis

Genetic tests: analysis of a sample of your blood or bone marrow tissue to study the genetic make-up

If these tests confirm a diagnosis of myelofibrosis, you will continue to see a hematologist/oncologist, the doctor who treats blood cancers.

Myelofibrosis is not usually curable so it is important to think about how your life may change. A chronic illness becomes part of who you are and how you live your life. A diagnosis of myelofibrosis may require changes in your routine, how you care for yourself or what you need from others in your life. It does not, however, define you. You are not your disease.


Treatment Options & Side Effects

Treatment for myelofibrosis can involve many different doctors, including a hematologist/oncologist, a surgeon, a radiation oncologist, and/or a stem cell transplant specialist. Your healthcare team also may include an oncology nurse, a nurse navigator, a counselor or social worker, and a pharmacist. These people can help you find information and resources that may be useful before, during, and after treatment.

Ask your doctor about the other members of your healthcare team, their names, and how you can meet them. You also may want to ask your insurance company to assign you a case manager to help you understand which treatments and services your health insurance will cover.

Side Effects Management

Side effects vary by treatment. The following is a list of selected treatments and possible side effects:

Chemotherapy: The side effects of chemotherapy depend on the drugs and the dose and may include hair loss, loss of appetite, nausea and vomiting, diarrhea, fatigue, and mouth sores.

Androgen therapy: These drugs can harm the liver, and, therefore, require close monitoring through blood tests and ultrasounds. They also can cause facial hair growth and other masculinizing effects in women.

Glucocorticoids: There are a number of possible side effects, most of which are manageable when used for a short time.

JAK inhibitors: Side effects can include an increased risk of bleeding and infection, bruising, dizziness and headaches.

Surgical removal of the spleen (splenectomy): Surgical removal of the spleen can cause side effects. You should be closely monitored for complications.

Stem cell transplantation: This treatment has very high risks, and is not an option for everyone.

Non-myeloablative stem cell transplant: Side effects can include headache, diarrhea, weakness, nausea, and dizziness.

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