Acute myeloid leukemia
ACUTE MYELOID LEUKEMIA
ACUTE MYELOID LEUKEMIA DEFINITION
Acute myelogenous leukemia (AML) is a cancer of the blood and bone marrow — the spongy tissue inside bones where blood cells are made.
The word “acute” in acute myelogenous leukemia denotes the disease’s rapid progression. It’s called myelogenous (my-uh-LOHJ-uh-nus) leukemia because it affects a group of white blood cells called the myeloid cells, which normally develop into the various types of mature blood cells, such as red blood cells, white blood cells and platelets.
Acute myelogenous leukemia is also known as acute myeloid leukemia, acute myeloblastic leukemia, acute granulocytic leukemia and acute nonlymphocytic leukemia.
ACUTE MYELOID LEUKEMIA CAUSES
A risk factor is anything that can increase your chance of developing a disease. Different cancers and leukaemias have different risk factors. We don’t know what causes most cases of leukaemia. But there are some factors that may increase your risk of AML.
Remember that having one or more risk factors does not mean that you will definitely get acute myeloid leukaemia. Many people with one or more risk factors never get it. And sometimes people with none of these risk factors develop AML. Risk factors are only a guide to what may increase risk. Some factors may lower the risk of developing leukaemia.
ACUTE MYELOID LEUKEMIA PATHOPHYSIOLOGY
The underlying pathophysiology in AML consists of a maturational arrest of bone marrow cells in the earliest stages of development. The mechanism of this arrest is under study, but in many cases, it involves the activation of abnormal genes through chromosomal translocations and other genetic abnormalities.
This developmental arrest results in 2 disease processes. First, the production of normal blood cells markedly decreases, which results in varying degrees of anemia, thrombocytopenia, and neutropenia. Second, the rapid proliferation of these cells, along with a reduction in their ability to undergo programmed cell death (apoptosis), results in their accumulation in the bone marrow, the blood, and, frequently, the spleen and liver.
ACUTE MYELOID LEUKEMIA SYMPTOMS
General signs and symptoms of the early stages of acute myelogenous leukemia may mimic those of the flu or other common diseases. Signs and symptoms may vary based on the type of blood cell affected.
Signs and symptoms of acute myelogenous leukemia include:
- Bone pain
- Lethargy and fatigue
- Shortness of breath
- Pale skin
- Frequent infections
- Easy bruising
- Unusual bleeding, such as frequent nosebleeds and bleeding from the gums
ACUTE MYELOID LEUKEMIA DIAGNOSIS
Going to your GP
If you have worrying symptoms, you usually begin by seeing your family doctor. Your GP will examine you and ask about your general health and symptoms. This will include
- What your symptoms are
- When you get them
- Whether anything you do makes them better or worse
- Your doctor will examine you by
- Feeling for swollen organs or glands
- Looking for signs of abnormal bleeding
- Your GP will also ask you to have a blood test.
At the hospital
If your GP thinks that you may have leukaemia, they will suggest you go and see a specialist doctor called a haematologist (pronounced heem-at-oll-oh-jist). Haematologists treat diseases of the blood. Your haematologist will ask you to have some tests. These might include
- Blood tests
- Bone marrow tests
- Chest X-ray
Blood tests are the most important tests for acute leukaemia. Your doctor or nurse takes a small amount of blood from a vein in your arm, using a needle and syringe. They send your blood to the laboratory. A haematologist looks at the sample under a microscope to count the different blood cells. They call this a full blood cell count (FBC).
Many people with AML have a low white blood cell count. If your white count is high, it can be due to a large number of early (immature) white blood cells called blasts.
Your doctor may also do other blood tests to see how well your liver and kidneys are working.
Bone marrow test
Blood cells grow in your bone marrow. So your specialist may want to check a sample of your bone marrow for signs of leukaemia or other illnesses. There are 2 different types of bone marrow test. You may hear them called
- Bone marrow aspiration
- Bone marrow biopsy or trephine biopsy
- Bone marrow aspiration
In a bone marrow aspiration, the doctor puts a thin needle into the centre of one of your bones. They then draw out some of the liquid bone marrow. Usually, the doctor takes the sample from one of your hip bones. You have a local anaesthetic injection first.
Bone marrow biopsy or trephine biopsy
In a bone marrow biopsy, the doctor uses a slightly larger needle to remove a small amount of bone and marrow together.
You usually have an aspiration and biopsy at the same time. There is information about having a bone marrow test in the cancer tests section.
As well as looking at the bone marrow cells, the haematologist will test for abnormalities in yourchromosomes. These tests are called cytogenetics (pronounced sigh-toe gen-et-ics). The haematologist will also do tests for particular proteins made by some types of leukaemia cells. This is called immunophenotyping (pronounced imm-you-no-fee-no-typing).
You may have X-rays to check your general health.
ACUTE MYELOID LEUKEMIA TREATMENT
Treatment of acute myelogenous leukemia depends on several factors, including the subtype of the disease, your age, your overall health and your preferences.
In general, treatment falls into two phases:
- Remission induction therapy. The purpose of the first phase of treatment is to kill the leukemia cells in your blood and bone marrow. However, remission induction usually doesn’t wipe out all of the leukemia cells, so you need further treatment to prevent the disease from returning.
- Consolidation therapy. Also called post-remission therapy, maintenance therapy or intensification, this phase of treatment is aimed at destroying the remaining leukemia cells. It’s considered crucial to decreasing the risk of relapse.
Therapies used in these phases include:
- Chemotherapy. Chemotherapy is the major form of remission induction therapy, though it can also be used for consolidation therapy. Chemotherapy uses chemicals to kill cancer cells in your body.
People with AML generally stay in the hospital during chemotherapy treatments because the drugs destroy many normal blood cells in the process of killing leukemia cells. If the first cycle of chemotherapy doesn’t cause remission, it can be repeated.
- Other drug therapy. Arsenic trioxide (Trisenox) and all-trans retinoic acid (ATRA) are anti-cancer drugs that can be used alone or in combination with chemotherapy for remission induction of a certain subtype of AML called promyelocytic leukemia. These drugs cause leukemia cells with a specific gene mutation to mature and die, or to stop dividing.
- Stem cell transplant. A stem cell transplant, also called a bone marrow transplant, may be used for consolidation therapy. A stem cell transplant helps re-establish healthy stem cells by replacing unhealthy bone marrow with leukemia-free stem cells that will regenerate healthy bone marrow.
Prior to a stem cell transplant, you receive very high doses of chemotherapy or radiation therapy to destroy your leukemia-producing bone marrow. Then you receive infusions of stem cells from a compatible donor (allogeneic transplant).
You can also receive your own stem cells (autologous transplant) if you were previously in remission and had your healthy stem cells removed and stored for a future transplant.
- Clinical trials. Some people with leukemia choose to enroll in clinical trials to try experimental treatments or new combinations of known therapies.