What is Myelofibrosis?
Myelofibrosis is a rare type of chronic leukemia, which is a cancer, affecting the tissues which help in formation of blood in the body. Myelofibrosis is a fatal disorder of the bone marrow which disturbs the normal production of the blood cells in the body. This results in massive scarring in the bone marrow leading to severe anemia, fatigue, weakness and usually an enlarged liver and spleen. Myelofibrosis is classified as one of the group of diseases known as myeloproliferative disorders. Individuals suffering from myelofibrosis worsen continuously and there are some who can also develop a more serious type of leukemia. However, there are some patients who have myelofibrosis and yet live without experiencing any symptoms for many years. Treatment for myelofibrosis aims at relieving symptoms and consists of different options which are explained in this article in detail.
Causes of Myelofibrosis
The cause of development of Myelofibrosis is genetic mutation in the blood stem cells. However, the exact cause of the genetic mutation in the cells of the blood is not clear. The genetic mutation in myelofibrosis is also known as JAK2. There are other genetic mutations, which can be associated with myelofibrosis.
The blood stem cells have the capacity to undergo replication and can divide into multiple specialized cells, which form our blood, such as red blood cells, platelets and white blood cells. As there is replication and division in the mutated blood stem cells, the mutation is passed onto the new cells. As the production of the newly mutated cells increase, they start having disastrous effects on the production of the blood resulting in decrease in the red blood cells and anemia, which is the primary characteristic of myelofibrosis along with excessive white blood cells with changes in platelets levels. There is scarring of the bone marrow, instead of it being spongy, in patients suffering from myelofibrosis.
Risk Factors for Myelofibrosis
- Having another blood cell disorder, such as polycythemia vera or essential thrombocythemia, increases the tendency to develop Myelofibrosis as a result of complication of essential thrombocythemia.
- Myelofibrosis can develop in people of any age, however, it is most commonly diagnosed in individuals who are aged about 50 to 60.
- Individuals who have had exposure to certain chemicals, such as benzene and toluene, have a higher risk of developing myelofibrosis.
- Individuals who are exposed to high levels of radiation have an increased risk of developing myelofibrosis.
Signs & Symptoms of Myelofibrosis
Myelofibrosis tends to develop gradually. In the initial stages of myelofibrosis, many patients do not experience any symptoms. However, as there is increase in the disruption of production of healthy blood cells, patients start experiencing signs and symptoms including:
- Anemia, which causes weakness, tiredness, and shortness of breath.
- Pallor of the skin.
- Feeling of fullness or pain below the ribs, on the left side due to an enlarged spleen.
- Easy bleeding.
- Easy bruising.
- Night sweats, i.e. excessive sweating during sleep.
- Tendency towards frequent infections.
- Pain in the bone.
Diagnosis of Myelofibrosis
- Physical examination is done by the doctor where the patient's vital signs are checked, such as pulse rate and blood pressure. Other than this, the spleen, abdomen and lymph nodes are also palpated/ checked.
- Blood tests help in diagnosis of myelofibrosis, as they helps in revealing the abnormally low levels of red blood cells, which happens in anemia and is an indication of myelofibrosis. There is abnormality in the levels of white blood cells and platelets also such as increased levels of white blood cells and varying levels of platelets.
- Imaging tests, such as x-rays and magnetic resonance imaging (MRI), help in giving additional information about myelofibrosis.
- Bone marrow tests, including bone marrow aspiration and biopsy, help in confirming the diagnosis of myelofibrosis.
- Gene tests are carried out on sample of bone marrow or blood to look for gene mutations in the blood cells, which are associated with myelofibrosis.
Treatment of Myelofibrosis
If the patient is not experiencing any symptoms and does not exhibit any signs of Myelofibrosis such as anemia, enlargement of spleen or liver, then immediate treatment is not usually required. In such cases, the patient is closely observed through regular health checkups and exams, to look for any progression of disease.
There are some patients who can remain symptom-free for many years.
Treatment comprising of Targeting the Gene Mutations occurring in Myelofibrosis
Research is going on for development of medications, which specifically target the JAK2 gene mutation, which is considered responsible for myelofibrosis. Ruxolitinib is once such medication, which along with other new medications, is being tested in clinical trials and have shown to be helpful in reducing the size of the enlarged spleen and in alleviating the symptoms of myelofibrosis. Ruxolitinib acts by stopping the action of the JAK-related genes present in the healthy cells as well as the diseased cells. As the healthy cells are also affected, patient can experience side effects, such as bleeding, bruising, infection, headaches and dizziness.
Treatment for Anemia in Myelofibrosis
For severe anemia resulting from myelofibrosis, treatment which is done includes:
- For severe anemia, regular blood transfusions are done to help increase the red blood cells and to alleviate the symptoms of anemia, such as weakness and fatigue. In some cases, medications can also help in improving the anemia.
- Androgen therapy comprising of synthetic version of the androgen, which is a male hormone, helps in boosting the production of red blood cells and improving severe anemia. There are risks with androgen therapy, such as liver damage and masculinizing effects in women.
- Medications, such as thalidomide and other associated medications like pomalidomide and lenalidomide can also help in improving the levels of blood cells and can also help in decreasing the size of the enlarged spleen. These drugs can also be given in conjunction with steroids. There is a risk of serious birth defects with these medicines and they are still being studied in clinical trials.
Treatment for Enlarged Spleen in Myelofibrosis
- Splenectomy is a procedure where the spleen is removed surgically. This is done if patient is having pain and other complications from the spleen enlargement. Splenectomy is also done if the patient is not responding to other type of therapy and has a chance to benefit from surgical removal of the spleen. The risks of splenectomy include excessive bleeding, infection, and formation of blood clots, which can cause pulmonary embolism or stroke. After splenectomy, some patients can experience enlargement of the liver and a great increase in platelet count.
- Radiation therapy helps in reducing the size of the spleen, where the cells are destroyed with the use of high-powered beams, such as x-rays. Radiation therapy is done when splenectomy is not an option for the patient.
- Chemotherapy comprises of drugs, which can help in reducing the size of the enlarged spleen by killing the cells and help in relieving related symptoms including pain.
Treatment of Myelofibrosis by Stem Cell Transplantation (Bone Marrow Transplantation)
- Allogeneic stem cell transplantation, where transplantation of stem cells is done from a compatible donor, is the only treatment which has the possibility to cure myelofibrosis. However, this treatment also carries a high risk of fatal side effects. Factors which are responsible for the patient to qualify for this treatment of myelofibrosis include age, the severity of the disease and other health issues.
- Before doing stem cell transplantation, the patient is given very high doses of radiation therapy or chemotherapy to destroy the diseased or scarred bone marrow. After which, the patient is given stem cell infusions from a suitable donor.
- There is always a risk of the new stem cells reacting against the healthy tissues of the body resulting in potentially serious damage.
- Other risks of this procedure include damage to the blood vessel/ organ, cataracts, and development of a different type of cancer down the road.
Prognosis & Life Expectancy in Myelofibrosis
Myelofibrosis has no cure. This means that the patient will die eventually. The prognosis and life expectancy of an individual suffering from Myelofibrosis varies from patient to patient. The prognosis and life expectancy in Myelofibrosis depends on the severity of the disease, its progression, and at what stage the treatment has begun along with the general health of the patient. The life expectancy or survival rate of the patient can be anywhere from a year to year-and-a-half.