Myelofibrosis – An Overview
Definition of myelofibrosis
Myelofibrosis is an incurable bone marrow disorder that disrupts the body’s normal production of blood cells. It is classed as a blood cancer, a form of chronic leukemia. The result is extensive scarring in the bone marrow, leading to severe anaemia, weakness, fatigue, and often, an enlarged spleen and liver.
Myelofibrosis is also called agnogenic myeloid Metaplasia or idiopathic myelofibrosis and it can occur at any age, although it tends to be diagnosed in those over 50 years of age.
Symptoms of myelofibrosis
Myelofibrosis usually develops slowly. In its early stages, most people do not notice any symptoms of the disorder, but as production of normal blood cells decreases, the symptoms may include:
- A feeling of tiredness, weakness or shortness of breath, partly because of anaemia
- A feeling of bloating or fullness in the abdomen, particularly on the left side, due to the spleen becoming enlarged..
- Enlarged liver
- Pale skin
- Easy bruising
- Easy bleeding
- Night sweats
- Frequent infections
- Bone pain
- Feeling run down or tired
- Unexplained weight loss
These signs and symptoms, however vague they might be, should be brought to the attention of your doctor.
Myelofibrosis is a progressive disorder, and some patients eventually develop a severe form of leukaemia. However it is also possible to have myelofibrosis and live symptom-free for many years.
How myelofibrosis occurs
Production of blood cells in the body is called hematopoiesis. It all begins with a particular bone marrow cell called a hematopoietic stem cell. Stem cells are primitive undefined cells that are able to replicate into the more specialized red blood cells, white blood cells and platelets.
Blood cells have a limited life. They age and die off naturally, to be replaced by new cells in a continuous, healthy cycle.
Myelofibrosis occurs when a single stem cell mutates. It is not known what causes this mutation, however, it is probably as a result of exposure to some environmental agent (e.g. chemicals or radiation), rather than one which is present at birth (congenital).
If this mutated cell replicates itself, it passes the mutation on to the new cells. As many more of these mutated cells are produced, they start to have serious consequences on normal blood production with the end result, normally, being a lack of red blood cells which causes anaemia, a characteristic of myelofibrosis. Often, an over abundance of white blood cells occurs, with platelet levels being variable.
Due to this overproduction of white blood cells, doctors sometimes refer to myelofibrosis as a myeloproliferative disorder, a disease characterized by uncontrolled production of one or more types of blood cells. The scarring of the bone marrow (fibrosis) is sometimes considered a secondary activity of the mutated cells. The spleen (and sometimes the liver) become enlarged when they shed the excess of mutated red blood cells and white cells that circulate through your body. It has been found that the proteins produced by the mutated cells can cause the bone marrow to become leaky, allowing bone marrow cells to leak into the blood stream, which adds to the workload of the spleen, also causing it to enlarge.
Risk factors of myelofibrosis
If problems arise, your doctor may recommend removal of your spleen although this is not as common today as it is considered my many doctors in this field to be counter productive as it may cause complications worse than leaving it in place and may shorten life expectancy.
- Myelofibrosis can occur at any age, but is usually diagnosed in people over the age of 50. Myelofibrosis is usually much more uncommon in children, except for a form that may be genetic within families. Some people with myelofibrosis have a mutation in the JAK2 or MPL gene.
- Exposure to toxins. In a few cases, myelofibrosis has been associated with exposure to carcinogenic substances such as thorium dioxide, toluene and benzene and exposure to ionising radiation. Some people who received an X-ray contrast material called Thorotrast in the 1930s and 1940s has since developed myelofibrosis.
How Common Is Myelofibrosis
A study by the Mayo Clinic reported an incidence of 1.46 per 100,000 individuals and an average survival of 7 years from diagnosis. Another study has evaluated national databases and estimates the number of new cases per year to be 0.41 cases per 100,000 in the general population. In other words, myelofibrosis is considered to be quite rare.
Complications of myelofibrosis
Complications that may result from myelofibrosis include:
- As the spleen grows there is increased pressure on blood flowing into the liver. Normally, the blood flows from the spleen to the liver through a large vein called the portal vein. The increased blood flow from an enlarged spleen can cause high blood pressure in the portal vein (portal hypertension) and this may in turn force the excess blood into smaller blood vessels in the stomach and esophageus, potentially causing these blood vessels to crack and bleed.
- Pain in the upper left hand side and shoulder. This may be due to episodes of inflammation or tissue death in the spleen. Pain relief can usually help control this pain.
- Formation of blood cells outside of the bone marrow (extramedullary hematopoiesis) can result in lumps or tumors for the production of blood cells in other areas of the body. These tumors can cause bleeding in the gastrointestinal tract, coughing or spitting up of blood, compression of the spinal cord, or convulsions. These blood producing tumors are usually treated with low doses of radiation.
- White blood cells help fight infection. However, in myelofibrosis, these white cells are often not fully formed or are mutated, so they become ineffective, and actually reduce the ability to fight infection.
- As myelofibrosis progresses, the platelet count tends to fall below its normal level (thrombocytopenia) and platelet deficiency occurs. Insufficient numbers of platelets can cause abnormal bleeding, a problem that you will want to discuss with your doctor if you are considering any surgical procedure.
- Myelofibrosis can lead to a hardening of the bone marrow and an inflammation of the connective tissue around the bone. This leads to severe bone and joint pain.
- Myelofibrosis increases the body’s production of uric acid, which is a by-product of the breakdown of purines, a substance found naturally in the body and in many foods. An excess of uric acid can lead to needle-like deposits in the joints and causes joint pain and inflammation known as gout. You may need medication to keep the levels of uric acid normal.
- Some people with myelofibrosis will eventually develop acute myelogenous leukaemia, a type of blood and bone marrow cancer that progresses quickly.
Seeing a heamatologist about myelofibrosis
If your doctor suspects that you have myelofibrosis, usually based on an enlarged spleen and abnormal blood tests, they will probably refer you to a haematologist who is a specialist in the field of blood diseases. Myelofibrosis is a complex disease and you will probably feel more comfortable if you are well prepared for your visit. These suggestions may help:
- When you call to make your appointment, ask if you need to prepare for any diagnostic tests you may need to have. For example, you may need to avoid eating and drinking, or stop some medications you are taking, before certain tests.
- Myelofibrosis does not cause any problem in its early stages, but as the disease progresses, the signs and symptoms begin to occur. Be sure to note down any changes in your health and the time frame over which these changes have occurred.
- Write down a list of all the medications you are taking, including over-the-counter drugs, vitamins and herbs. Use the original containers to help you write your list and include the doses and directions.
- During the appointment, don’t be afraid to ask questions if you do not understand what your doctor says. Cover the issues that affect you the most. If you forget to ask about something concerning myelofibrosis, call and leave a message for your doctor asking those questions.
- As it may be hard for you to absorb all the information provided to you during your appointment, it is advisable for you have someone accompany you to your appointment, as they may remember something you’ve forgotten or missed.
Tests and diagnosis for myelofibrosis
For people who have no symptoms of myelofibrosis, a routine medical check may reveal an enlarged spleen and/or abnormal blood test results. These will cause suspicions that a medical problem exists. However, if you go to the doctor because of troublesome symptoms, a physical examination and blood tests are usually the first steps your doctor will undertake to determine a diagnosis for myelofibrosis.
To confirm a diagnosis of myelofibrosis, you will need some form of depiction of your bones, spleen and liver, and an examination of a sample of bone marrow.
- Your doctor will need to perform a thorough physical examination. This should include a check of your vital signs, such as heart rate and blood pressure, as well as checks of your lymph nodes, spleen and stomach.
- In myelofibrosis, a complete blood count usually shows abnormally low levels of red blood cells. This is a sign of anaemia, common in people with myelofibrosis. White blood cells and platelets are usually abnormal too. Often, white blood cells are higher than normal, but in some people they may be normal or even below normal. Platelet count may be higher or lower than normal.
- Imaging test such as ultrasound, magnetic resonance imaging (MRI) and computed tomography (CT) scans to help determine whether your spleen and liver are enlarged. Your doctor may be able to detect an enlarged spleen by feeling your abdomen, but imaging tests can help identify the degree of enlargement.
- Bone marrow biopsy and aspiration is important to confirm a diagnosis of myelofibrosis. This is a more invasive procedure and it is usually done last, to confirm other test results. In a bone marrow biopsy, a special needle is used to draw a sample of bone marrow from hip. During this procedure, an aspiration needle is used to withdraw a sample of the liquid portion of your bone marrow. Studying the genetic components (cytogenetic studies) of the bone marrow stem cell test can reveal chromosomal abnormalities and can help rule out other types of bone marrow diseases.
Treatments and medications for myelofibrosis
If you do not experience symptoms of myelofibrosis, that is no signs of anaemia, an enlarged spleen or other complications, treatment is usually not needed. Instead, your doctor will probably monitor your health closely through regular checkups and examsinations, and look out for signs of the disease progressing. Some people remain symptom-free many years.
For people with severe symptoms or complications, treatment options typically include:
- If you have severe anaemia, periodic transfusions of red blood cells will be needed to increase the red cell count and ease the anaemia symptoms, such as fatigue and weakness. Sometimes drugs can help improve blood production, so you are less likely to need blood transfusions. These drugs don’t work on most people and your doctor may advise against them.
- A synthetic version of the male hormone androgen, in combination with a corticosteroid medication such as prednisone, can stimulate production of red blood cells in some people which can improve severe anaemia. People who respond to this treatment after one month usually continue the androgen and slowly reduce the prednisone. Androgen therapy has considerable risks, including liver damage, masculinization effects in women, and the growth of cancer cells.
- Hydroxyurea (Hydrea) is the most used drug in the chemotherapy treatment of myelofibrosis. Hydroxyurea can reduce the size of an enlarged spleen, reduce high blood platelet count, improve night sweats and weight loss, and possibly reduce bone marrow fibrosis. However, it does not have a great success rate.
- Radiation treatment may help a few people who have pain in the bones. It may also help reduce the size of the spleen, particularly as surgical removal is often not an option.
- Using thalidomide combined with prednisone may help to reduce spleen size, improve anaemia, white blood cells and platelets in some people. Improvement of other systemic symptoms such as weakness, fatigue, night sweats and shortness of breath may also occur. This therapy may also reduce the need for blood transfusions, but it’s still being trialed.
- Surgical removal of the spleen (splenectomy). If the size of your spleen is sore and starting to cause harmful complications, and if you do not respond to other forms of therapy, you may benefit from your spleen being surgically removed. However, risks including infection, excessive bleeding, blood clot formation leading to stroke or pulmonary embolism, and a higher incidence of conversion to acute leukaemia. After surgery, some people experience liver enlargement and an abnormal increase in platelet count. Due to these complications, splenectomy is usually not recommended.
- Allogeneic stem cell transplantation from a suitable donor is currently the only treatment that has the potential to cure myelofibrosis. It also has a high risk of life-threatening side effects, because it requires high doses of chemotherapy and radiation before the transplant to destroy the diseased cells. After surgery, there is a risk that the new stem cells will respond to the healthy tissues of your body, causing potentially fatal damage (graft-versus-host disease). Other risks include organ or blood vessel damage, cataracts, and developing a second cancer later. Most people with myelofibrosis, because of age, stability of the disease or other health problems, do not qualify for this treatment.
Current research into myelofibrosis
There is some research being conducted into reduced intensity transplant, also known as nonmyeloablative transplant or mini-transplant. Reduced intensity transplants use lower doses of pre-transplant chemotherapy and radiation, instead relying on the donor’s immune system to destroy the diseased cells. However, even reduced intensity transplants have side effects. Doctors hope that it will be safer, but equally effective as the more aggressive, standard transplant treatments.
The best hope for a treatment for myelofibrosis lies in the clinical trials now being conducted by many pharmaceutical companies using mutation inhibitors. The JAK 2 mutation is a common mutation in many myeloproliferative disorders, and this is the main thrust of the research. The cause of myelofibrosis is usually not known, however, certain factors are known to increase your risk. There have been some very good results from these studies, even with patients who do not have the JAK 2 mutation.
Coping and support – living with myelofibrosis
Living with myelofibrosis will often mean dealing with pain, discomfort, uncertainty and adverse long-term treatments. The following things can help ease the challenge and make you feel more comfortable and in charge of your health:
- Learn about your condition. Myelofibrosis is fairly uncommon. I have set up this website to bring together various sources of information to help you get accurate, reliable and up to date information
- Get support. Use that opportunity to lean on friends and family. It can be hard to talk about your diagnosis, and you will probably have a variety of reactions when you share the news. But to talk about your diagnosis and share information about your illness with others can help. So can the outpouring of practical help that often results. You can also benefit from attending a support group, either in your community or on the Internet. A group of people with the same or a similar diagnosis, such as a myeloproliferative disorders, can be a source of helpful information, practical tips and encouragement. If nothing else, you realise that you are not suffering alone, there are actually other people suffering with you.
- Find ways to manage your disease. If you have myelofibrosis, you may face frequent blood tests and medical appointments, regular bone marrow examinations or transfusions. Some days you feel sick, even though you may not look sick. And some days, you just feel sick and tired of feeling sick and tired. Try to find some activities that help, whether it’s yoga, exercise, social outings or adopting a more flexible work schedules. Talk to a counselor, therapist or oncology social worker if you need help dealing with the emotional costs associated with this disease. Just don’t give up on life, you can still be productive and have quality of life.
Although the information on this web site is not unique to myelofibrosis in Australia, my hope is this aggregation of information in one place is helpful to everyone looking for information on myelofibrosis.
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