# Myelofibrosis
What is it
Myelofibrosis is a rare blood cancer in which the bone marrow (where blood cells are made) increasingly develops scar tissue. This tissue gradually replaces healthy blood-forming cells. As a result, fewer and fewer blood cells are produced, leading to anemia, susceptibility to infection, and other serious problems.
Myelofibrosis belongs to a group of diseases called 'myeloproliferative neoplasms' — conditions in which certain blood cells multiply uncontrollably. In myelofibrosis, certain bone marrow cells (fibroblasts) in particular form excessive scar tissue.
The disease usually occurs in adulthood, especially from age 50 onwards. It can occur as primary myelofibrosis (develops on its own) or develop from other blood disorders such as essential thrombocythemia or polycythemia vera.
Causes
Most patients have mutations in genes involved in controlling the blood system. The most common are mutations in *JAK2*, *CALR*, and *MPL*. These genes normally regulate the growth and division of blood cells. When they are mutated, this process gets out of control.
It is unclear why these mutations occur. They are not inherited (you are not born with this mutation) and are not related to your lifestyle. The mutation occurs randomly at a given moment in one blood cell, which then divides uncontrollably.
Due to the vigorous growth of these cells, an inflammatory reaction occurs in the bone marrow, which ultimately leads to scar formation.
How the disease progresses
Myelofibrosis usually progresses in stages. In the early phase, people can live with few complaints, but the disease typically develops toward more severe forms independently of treatment.
In recent years, new treatments have become available (especially JAK inhibitors) that can slow the course and reduce symptoms. These give many patients more time with better quality of life. The disease itself does not cure with these medications, but is better managed.
In some patients, myelofibrosis can progress to acute leukemia — a more aggressive form of cancer.
Stem cell transplantation (in which healthy blood-forming cells from a donor are transplanted) may be an option for younger, fit patients, but this is an intensive treatment with risks.
Symptoms by phase
**Early phase**
At first, many people feel little or nothing. Sometimes myelofibrosis is discovered by chance during routine blood work.
Some patients already experience fatigue, light night sweats, or a feeling of fullness under the ribs (because the spleen is enlarged) in this phase.
**Advanced phase**
As the disease progresses, more symptoms appear:
- **Severe fatigue** — this is often the most burdensome symptom
- **Bleeding tendency** — bruising or nosebleeds, because there are too few platelets
- **Frequent infections** — due to lack of white blood cells
- **Shortness of breath** — due to anemia
- **Pain or fullness lower left** — due to enlargement of the spleen
- **Bone and abdominal pain** — due to spread of anemia to bones and organs
- **Night sweats** — can be bothersome
**Late phase**
With further progression, complications can arise:
- Severe anemia
- Blood clots (for example, in blood vessels)
- Progression to acute leukemia
- Organ damage from complications
What it means for daily life
Myelofibrosis has a major impact on daily activities. The severe fatigue is the most difficult aspect for many patients: work, household chores, hobbies, and social activities become arduous.
Because infections are a risk, some patients must be careful with contact during viral epidemics. Regular doctor visits, blood tests, and possibly infusions or treatments become part of the routine.
Many people struggle with fear — of deterioration, of complications such as blood clots, and of transformation into leukemia. Physical discomfort (pain, sweating) disrupts sleep and wellbeing.
Financial concerns can arise from work loss or treatment costs, although myelofibrosis care in the Netherlands is usually well covered by insurance.
Psychosocial support (social work, psychologists, peer contact) can help with these burdens.
Outlook
The outlook for myelofibrosis has improved over recent decades thanks to new medicines. JAK inhibitors have given many patients years of reasonable quality of life.
At population level, studies around 2020–2025 reported median survival times of 4 to 8 years after diagnosis, depending on risk factors at diagnosis. But this says little about your personal situation — someone can live much longer, especially with new treatments.
Younger, fit patients who are eligible for stem cell transplantation sometimes have a chance of longer survival, but this carries major risks.
Research is now focusing on:
- Better combinations of medicines
- Treatments more specifically targeting the underlying mutation
- Better selection of patients for invasive treatments
- Treatment of complications such as thrombosis
Many patients and doctors focus on quantity and quality of life: living as long as possible *with* the best possible daily functioning.
Frequently asked questions
**Is myelofibrosis hereditary? Will my children get it too?**
No. Myelofibrosis is caused by mutations that occur in a single blood cell, usually later in life. This is *not* hereditary — you were not born with this mutation and you do not pass it on to children. The risk for family members is not increased.
**Can myelofibrosis be cured?**
Not at present with standard medicines. JAK inhibitors and other substances help reduce symptoms and keep the disease under control, but they do not cure it. Stem cell transplantation can in rare cases lead to long-term remission or cure, but this does not always work and carries serious risks. Research is focused on better treatments.
**What is the difference between myelofibrosis and leukemia?**
Myelofibrosis is a chronic (long-term) condition in which the bone marrow becomes scarred and blood cell production decreases. Acute leukemia is much more aggressive — young, immature cancer cells multiply extremely fast. In approximately 10–15% of myelofibrosis patients, the disease progresses to acute leukemia after years. Doctors call this 'transformation'. This is a serious complication that requires special treatment.
**How often do I need to see the doctor and what tests?**
This depends on your stage and treatment. In the beginning and during treatment, visits are usually monthly or more frequent, with blood tests. Later the frequency may decrease. Your doctor will clearly tell you what schedule applies to you. Regular contact is important to catch complications early.
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_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._