Myelofibrosis is a rare type of blood cancer where scar tissue forms in the bone marrow, disrupting its ability to produce normal blood cells. As the bone marrow becomes more fibrotic (scarred), it loses its ability to create essential blood components, leading to a range of complications. But what exactly is bone marrow fibrosis, and how does it connect to myelofibrosis? Here, we’ll explore these questions in detail, covering the root causes, symptoms, and available treatments.
What Is Myelofibrosis?
Myelofibrosis is a chronic blood disorder that affects the bone marrow, a spongy tissue found inside bones responsible for producing blood cells. When someone develops myelofibrosis, the bone marrow becomes fibrotic, meaning scar tissue gradually replaces healthy bone marrow tissue. This limits the bone marrow’s ability to create blood cells, causing complications like anaemia, bleeding issues, and an enlarged spleen.
Over time, myelofibrosis can develop into more severe forms of blood cancer, such as acute myeloid leukaemia (AML), further worsening the patient’s health.
What Are the Symptoms of Myelofibrosis?
The symptoms of myelofibrosis are caused by the inability of the bone marrow to produce sufficient blood cells, leading to:
- Severe fatigue: Due to anaemia, a condition where there aren’t enough red blood cells to carry oxygen around the body.
- Weakness and shortness of breath: Often linked to a lack of oxygen-rich red blood cells.
- Bleeding and bruising: Because of low platelet counts.
- Frequent infections: Due to a lack of white blood cells, which are vital for fighting infections.
- An enlarged spleen (splenomegaly): The spleen compensates for the bone marrow’s inability to produce blood cells, often becoming enlarged and causing discomfort in the abdomen.
How Does Bone Marrow Fibrosis Drive Myelofibrosis?
Bone marrow fibrosis occurs when scar tissue forms inside the bone marrow, preventing it from creating healthy blood cells. This fibrosis is triggered by abnormal signalling pathways, often involving mutations in genes like JAK2, which are frequently present in patients with myelofibrosis.
The JAK-STAT pathway is crucial in controlling blood cell production in patients with myelofibrosis, but mutations in this pathway lead to the uncontrolled production of fibrous tissue, which replaces normal bone marrow cells. This scar tissue hinders the production of blood cells, driving the progression of the disease.
What Causes Bone Marrow Fibrosis?
Several factors contribute to the development of bone marrow fibrosis, including:
- Genetic mutations: Many patients with myelofibrosis have mutations in the JAK2 gene, which leads to abnormal signalling and the overproduction of scar tissue in the bone marrow.
- Chronic inflammation: Inflammation can accelerate fibrosis by promoting the production of fibrous tissue within the bone marrow.
- Abnormal cell signalling: Malfunctions in the way cells communicate can result in excessive collagen and fibrosis development.
Can Myelofibrosis Progress Into Acute Myeloid Leukemia?
Yes, myelofibrosis can progress into acute myeloid leukaemia (AML), a more aggressive type of blood cancer. Around 10% to 20% of people with myelofibrosis will develop AML. When this transformation occurs, patients experience a rapid increase in immature white blood cells, called blasts, which flood the bloodstream and crowd out healthy blood cells. AML is much more challenging to treat than myelofibrosis and often requires aggressive treatment.
How Is Myelofibrosis Treated?
While there is no cure for myelofibrosis, treatments focus on managing symptoms and slowing the disease’s progression. One of the most commonly used treatments is Ruxolitinib, sold under the brand name Jakavi 10mg Tablet. Here’s how it works:
- Targets the JAK-STAT pathway: By inhibiting the overactive JAK1 and JAK2 proteins, Ruxolitinib helps reduce abnormal signalling that leads to fibrosis.
- Reduces spleen size: It can help shrink an enlarged spleen, reduce abdominal discomfort, and improve quality of life.
- Improves blood counts: Patients may see improvements in their red blood cell and platelet counts, easing symptoms like fatigue and bleeding.
Other treatments include blood transfusions, androgens, and in more severe cases, stem cell transplantation, which offers the potential for a cure in some patients.
What Is the Life Expectancy for Myelofibrosis?
The prognosis for myelofibrosis varies depending on the stage of the disease and how well it is managed. In many cases, patients live for several years after diagnosis, but some progress rapidly to more severe forms of blood cancer, like acute myeloid leukaemia. The use of medicines can help slow the disease and improve quality of life, but bone marrow transplantation remains the only curative option for advanced myelofibrosis.
How Does Bone Marrow Transplantation Help in Treating Myelofibrosis?
Bone marrow transplantation (BMT), also known as hematopoietic stem cell transplantation, is the only potential cure for myelofibrosis. This treatment involves replacing the patient’s diseased bone marrow with healthy stem cells from a donor. These stem cells can produce healthy blood cells, effectively restoring the bone marrow’s function. However, BMT is risky and not suitable for all patients, especially older individuals or those with other health complications.