Definition
Acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia, is a type of cancer of the blood and bone marrow — the spongy tissue inside bones where blood cells are made. The word "acute" in acute lymphocytic leukemia comes from the fact that the disease progresses rapidly and creates immature blood cells, rather than mature ones. The "lymphocytic" in acute lymphocytic leukemia refers to the white blood cells called lymphocytes, which ALL affects. Acute lymphocytic leukemia is also known as acute lymphoblastic leukemia.
Bone Marrow and Blood
Bone marrow is the soft inner part of some bones, such as the skull, shoulder blades, ribs, pelvis, and bones in the spine. The bone marrow is made up of a small number of blood stem cells, more mature blood-forming cells, fat cells, and supporting tissues that help cells grow.
Blood stem cells go through a series of changes to make new blood cells. During this process, the cells develop into 1 of the 3 main types of blood cell components:
1. Lymphocytes
These are the main cells that make up lymphoid tissue, a major part of the immune system. Lymphoid tissue is found in lymph nodes, the thymus, the spleen, the tonsils and adenoids, and is scattered throughout the digestive and respiratory systems and the bone marrow.
Lymphocytes develop from cells called lymphoblasts to become mature, infection-fighting cells. The 2 main types of lymphocytes are B lymphocytes (B cells) and T lymphocytes (T cells).
2. Monocytes
These white blood cells, which are related to granulocytes, also help protect the body against bacteria. After circulating in the bloodstream for about a day, monocytes enter body tissues to become macrophages, which can destroy some germs by surrounding and digesting them.
3. Granulocytes
These are white blood cells that have granules in them, which are spots that can be seen under the microscope. These granules contain enzymes and other substances that can destroy germs, such as bacteria. The 3 types of granulocytes – neutrophils, basophils, and eosinophils – are distinguished by the size and color of their granules.
Signs and Symptoms
The signs and symptoms of ALL are variable but follow from bone marrow replacement and/or organ infiltration. They include:
Most of the time, no clear cause can be found for ALL. But the following may play a role in the development of leukemia in general:
Factors that may increase the risk of acute lymphocytic leukemia include:
Treatment
In general, treatment for acute lymphocytic leukemia falls into separate phases:
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ALL in older adults
Older adults, such as those older than 60, tend to experience more complications from ALL treatments. And older adults generally have a worse prognosis than children who are treated for ALL. Discuss your options with your doctor. Based on your overall health and your goals and preferences, you may decide to undergo treatment for your ALL. Some people may choose to forgo treatment for the cancer, instead focusing on treatments that improve their symptoms and help them make the most of the time they have remaining.
Acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia, is a type of cancer of the blood and bone marrow — the spongy tissue inside bones where blood cells are made. The word "acute" in acute lymphocytic leukemia comes from the fact that the disease progresses rapidly and creates immature blood cells, rather than mature ones. The "lymphocytic" in acute lymphocytic leukemia refers to the white blood cells called lymphocytes, which ALL affects. Acute lymphocytic leukemia is also known as acute lymphoblastic leukemia.
Bone Marrow and Blood
Bone marrow is the soft inner part of some bones, such as the skull, shoulder blades, ribs, pelvis, and bones in the spine. The bone marrow is made up of a small number of blood stem cells, more mature blood-forming cells, fat cells, and supporting tissues that help cells grow.
Blood stem cells go through a series of changes to make new blood cells. During this process, the cells develop into 1 of the 3 main types of blood cell components:
- Red blood cells. Red blood cells carry oxygen from the lungs to all other tissues in the body, and take carbon dioxide back to the lungs to be removed.
- Platelets. Platelets are actually cell fragments made by a type of bone marrow cell called a megakaryocyte. Platelets are important in plugging up holes in blood vessels caused by cuts or bruises.
- White blood cells (which include lymphocytes, granulocytes, and monocytes). White blood cells help the body fight infections.
1. Lymphocytes
These are the main cells that make up lymphoid tissue, a major part of the immune system. Lymphoid tissue is found in lymph nodes, the thymus, the spleen, the tonsils and adenoids, and is scattered throughout the digestive and respiratory systems and the bone marrow.
Lymphocytes develop from cells called lymphoblasts to become mature, infection-fighting cells. The 2 main types of lymphocytes are B lymphocytes (B cells) and T lymphocytes (T cells).
- B lymphocytes: B lymphocytes protect the body from invading germs by maturing into plasma cells, which make proteins called antibodies. The antibodies attach to the germs (bacteria, viruses, and fungi), which helps the immune system destroy them.
- T lymphocytes: There are several types of T cells, each with a special job. Some T cells can destroy germs directly, while others play a role in either boosting or slowing the activity of other immune system cells.
2. Monocytes
These white blood cells, which are related to granulocytes, also help protect the body against bacteria. After circulating in the bloodstream for about a day, monocytes enter body tissues to become macrophages, which can destroy some germs by surrounding and digesting them.
3. Granulocytes
These are white blood cells that have granules in them, which are spots that can be seen under the microscope. These granules contain enzymes and other substances that can destroy germs, such as bacteria. The 3 types of granulocytes – neutrophils, basophils, and eosinophils – are distinguished by the size and color of their granules.
Signs and Symptoms
The signs and symptoms of ALL are variable but follow from bone marrow replacement and/or organ infiltration. They include:
- Anemia
- Bone pain, joint pain (caused by the spread of "blast" cells to the surface of the bone or into the joint from the marrow cavity)
- Breathlessness
- Enlarged lymph nodes, liver and/or spleen
- Excessive and unexplained bruising
- Frequent or unexplained fever and infection
- Generalized weakness and fatigue
- Petechiae, which are tiny red spots or lines in the skin due to low platelet levels
- Pitting edema (swelling) in the lower limbs and/or abdomen
- Weight loss and/or loss of appetite
Most of the time, no clear cause can be found for ALL. But the following may play a role in the development of leukemia in general:
- Certain chromosome problems
- Exposure to radiation, including x-rays before birth
- Past treatment with chemotherapy drugs
- Receiving a bone marrow transplant
- Toxins such as benzene
Factors that may increase the risk of acute lymphocytic leukemia include:
- Previous cancer treatment. Children and adults who've had certain types of chemotherapy and radiation therapy for other kinds of cancer may have an increased risk of developing acute lymphocytic leukemia.
- Exposure to radiation. People exposed to very high levels of radiation, such as survivors of a nuclear reactor accident, have an increased risk of developing acute lymphocytic leukemia.
- Genetic disorders. Certain genetic disorders, such as Down syndrome, are associated with an increased risk of acute lymphocytic leukemia.
- Having a brother or sister with ALL. People who have a sibling, including a twin, with acute lymphocytic leukemia have an increased risk of ALL.
Treatment
In general, treatment for acute lymphocytic leukemia falls into separate phases:
- Induction therapy. The purpose of the first phase of treatment is to kill most of the leukemia cells in the blood and bone marrow and to restore normal blood cell production.
- Consolidation therapy. Also called post-remission therapy, this phase of treatment is aimed at destroying any remaining leukemia in the body, such as in the brain or spinal cord.
- Maintenance therapy. The third phase of treatment prevents leukemia cells from regrowing. The treatments used in this stage are often given at much lower doses over a long period of time, often years.
- Preventive treatment to the spinal cord. People with acute lymphocytic leukemia may also receive treatment to kill leukemia cells located in the central nervous system during each phase of therapy. In this type of treatment, chemotherapy drugs are often injected directly into the fluid that covers the spinal cord.
- Chemotherapy. Chemotherapy, which uses drugs to kill cancer cells, is typically used as an induction therapy for children and adults with acute lymphocytic leukemia. Chemotherapy drugs can also be used in the consolidation and maintenance phases.
- Targeted drug therapy. Targeted drugs attack specific abnormalities present in cancer cells that help them grow and thrive. A certain abnormality called the Philadelphia chromosome is found in some people with acute lymphocytic leukemia. For these people, targeted drugs may be used to attack cells that contain that abnormality. Targeted drugs include imatinib (Gleevec), dasatinib (Sprycel) and nilotinib (Tasigna). These drugs are approved only for people with the Philadelphia chromosome-positive form of ALL and can be taken during or after chemotherapy.
- Radiation therapy. Radiation therapy uses high-powered beams, such as X-rays, to kill cancer cells. If the cancer cells have spread to the central nervous system, your doctor may recommend radiation therapy.
- Stem cell transplant. A stem cell transplant may be used as consolidation therapy in people at high risk of relapse or for treating relapse when it occurs. This procedure allows someone with leukemia to re-establish healthy stem cells by replacing leukemic bone marrow with leukemia-free marrow from a healthy person.
A stem cell transplant begins with high doses of chemotherapy or radiation to destroy any leukemia-producing bone marrow. The marrow is then replaced by bone marrow from a compatible donor (allogeneic transplant). - Clinical trials. Clinical trials are experiments to test new cancer treatments and new ways of using existing treatments. While clinical trials give you or your child a chance to try the latest cancer treatment, treatment benefits and risks may be uncertain. Discuss the benefits and risks of clinical trials with your doctor.
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Older adults, such as those older than 60, tend to experience more complications from ALL treatments. And older adults generally have a worse prognosis than children who are treated for ALL. Discuss your options with your doctor. Based on your overall health and your goals and preferences, you may decide to undergo treatment for your ALL. Some people may choose to forgo treatment for the cancer, instead focusing on treatments that improve their symptoms and help them make the most of the time they have remaining.