Acute Lymphocytic Leukemia

Acute Lymphocytic Leukemia

Also called: ALL, ALL Leukemia, Acute Lymphoblastic Leukemia

Reviewed By:
Mark Oren, M.D., FACP

Summary

Acute lymphocytic leukemia (ALL) is a form of leukemia, or cancer of the body’s blood-forming cells. It is the most common form of leukemia in children, according to the American Cancer Society (ACS).

Also known as acute lymphoblastic leukemia, ALL affects the body’s blood making system, including bone marrow and the lymphatic system. ALL develops from lymphoblasts (a type of white blood cell) in the bone marrow. Bone marrow is the soft, inner component of bones, where white blood cells, red blood cells and platelets are formed.

In patients with ALL, the bone marrow manufactures a large number of abnormal white blood cells. Over time they increase, crowding out normal white blood cells, red blood cells and platelets. This results in anemia, bleeding disorders and a decreased ability to fight off infection.

ALL develops in the bone marrow but typically spreads quickly into the blood. Eventually it spreads further into the lymph nodes, the liver, the spleen, the brain, the spinal cord and the testicles. Without successful treatment, the disease is usually fatal.

The exact cause of ALL has not been identified. Researchers have gained a greater understanding of how specific changes in DNA can cause cells to develop into leukemia. In most cases of leukemia, the DNA chanes are acquired, occurring after birth, rather than inherited. A number of risk factors have also been identified, including age and exposure to high levels of radiation. 

Symptoms of ALL vary depending on where it has spread in the body. General signs and symptoms include weight loss, fever, loss of appetite and weakness.

ALL may be first diagnosed in routine blood tests. However, additional tests typically are necessary to examine blood and bone marrow cells. Diagnostic tests for ALL may include bone marrow tests and lumbar puncture. The treatment and prognosis for ALL depends on the subtype of the disease, as well as certain additional factors including the patient’s age. It may include chemotherapy, radiation therapy, and bone marrow/stem cell transplantation. ALL patients usually receive a combination of these therapies.

The ACS predicts that in 2007 there will be approximately 5,200 new cases of ALL in the United States. The disease is more common in children, with only 20 percent of cases occurring in adults. ALL is slightly more common in males than in females.

According to the Leukemia & Lymphoma Society, from 1995 to 2001, the five-year survival rate for acute lymphocytic leukemia was 65 percent. In 2007, the five-year survival rate in children 15 years old and younger increased to 87 percent. The improved survival rate is largely due to advances in treatment of the disease.

About acute lymphocytic leukemia (ALL)

Acute lymphocytic leukemia (ALL) is a type of leukemia, or cancer of the body’s blood-forming cells. It affects the body’s blood-making system, including bone marrow and the lymphatic system.

Also known as acute lymphoblastic leukemia, ALL develops from lymphocytes, a type of white blood cell, in the bone marrow. Bone marrow is the soft, inner component of bones. It is composed of blood-forming cells, fat cells, and tissues that support the growth of blood cells. All blood cells are produced in the bone marrow from stem cells and include:

  • White blood cells (cells that fight infection).
  • Red blood cells (cells that carry oxygen to tissues all over the body).
  • Platelets (cells that help develop blood clots and control bleeding).

ALL initially develops in the bone marrow but typically spreads quickly into the blood. Eventually it spreads further to other organs including the liver, brain, spinal cord and testicles.

Lymphocytes are one of the three main types of white blood cells. They are the chief type of cell found in the lymphoid tissue, a major part of the immune system. Lymphoid tissue is found in the bone marrow, as well as the lymph nodes, thymus, spleen, tonsils and adenoids. The two main types of lymphocytes are:

  • B lymphocytes (B-cells). B-cells defend the body from foreign substances (e.g., germs, viruses) by changing into plasma cells, which produce antibodies.   The antibodies attach themselves to foreign substances or threats which mark them for destruction.  
  • T lymphocytes (T-cells). T-cells recognize the infected cells and destroy them directly.

ALL can develop from early forms of either B-cells or T-cells. In patients with leukemia, the bone marrow manufactures a large amount of abnormal white blood cells. Since they are defective, these cells are unable to defend the body from disease. As the disease progresses they build up, crowding out normal white blood cells, red blood cells and platelets. As a result, the production of normal white blood cells is affected, and the body’s ability to fight infection is impaired. In addition, the decrease in production of red blood cells and platelets results in anemia and bleeding disorders. Eventually, the cancer cells spill into the bloodstream and spread to other areas of the body.

There are many different types and subtypes of leukemia. In general, the disease is first classified according to how quickly it progresses. The second classification is based on the type of white blood cell from which the leukemia developed. The abnormal cells may be considered mature or immature depending on the cell type.

Leukemia can develop in two families of blood cells, lymphocytes or myeloid cells at two different progressions, acute and chronic. ALL is classified as a lymphocytic leukemia because it develops from bone marrow lymphocytes. It is classified as acute because most of the abnormal cells are immature. These immature cells are also known as blasts. Acute forms of leukemia develop quickly and, without proper treatment, are often fatal within a few months.

According to the American Cancer Society (ACS), approximately 44,000 new cases of leukemia will be diagnosed in the United States in 2007. Of these new cases, about 5,200 will be ALL. Although the disease mainly occurs in children, about one-fifth of cases occur in adults. The ACS estimates that about 1,400 people will die from ALL in 2007. The mortality rate is higher for adults, who account for two-thirds of deaths from ALL each year in the United States. In addition, the disease is slightly more common in males than in females and much more common in whites than African Americans.

Risk factors and causes of ALL

The exact cause of acute lymphocytic leukemia (ALL) has not been identified. Researchers, however, have gained a greater understanding of how specific changes in DNA can cause bone marrow stem cells to develop into leukemia.

Some forms of cancer are caused by DNA mutations that “turn on” oncogenes (genes that speed up cell division) or “turn off” tumor suppressor genes (genes that slow down cell division or cause cells to die at the right time). In people with leukemia, these mutations are normally acquired after birth. The mutations may occur from exposure to radiation or cancer-causing chemicals, but many times the mutations occur for no apparent reason.

One form of DNA abnormality that can cause leukemia to develop is a translocation. A translocation is the transfer of DNA from one chromosome to another. This abnormality can turn on oncogenes which causes rapid cell division. The translocation that is most commonly seen in people with ALL is the Philadelphia chromosome. Named after the city in which it was discovered, this translocation occurs between chromosomes 9 and 22 and occurs in about 20 to 25 percent of cases of ALL. Although they occur less often, deletions (the loss of part of a chromosome) and inversions (the rearrangement of DNA in part of a chromosome) also can cause ALL to develop.

In addition, researchers have identified a number of factors that increase a person’s chances of developing ALL. These risk factors include:

  • Exposure to high levels of radiation. Patients who have received radiation therapy as treatment for other forms of cancer have an increased risk of developing ALL later in life. In addition, people exposed to radiation from atomic blasts (such as those in Japan during World War II) and nuclear accidents have an increased risk of developing the disease. Many researchers  have investigated the relationship of power lines and leukemia. They have not been able to definitively prove that electromagnetic field (EMF) exposure increases the risk of cancer. Most studies have indicated that there is either very little or no risk from exposure to EMF.
  • Chemotherapy. Patients treated with certain chemotherapy drugs are at an increased risk of developing leukemia later in life. This risk may be greater with those individuals who have received higher-than-standard chemotherapy treatments.
  • Human T-cell lymphoma/leukemia virus (HTLV-I). Infection with this virus can cause a rare type of ALL. The virus occurs most often in Japan and the Caribbean and is not common in the United States.
  • Burkitt lymphoma. A form of lymphoma (cancer of the lymphoid tissue), Burkitt lymphoma can form a type of ALL. It has been linked to infection with the Epstein-Barr virus (the virus that causes mononucleosis) and is more common in Africa.
  • Down syndrome and other specific genetic diseases. Patients with certain diseases caused by abnormal chromosomes may have an increased risk of developing ALL.
  • Race. White people have a higher risk of developing the disease than African Americans.
  • Age. The disease most often occurs in young children, typically between the ages of 3 and 6. The risk of developing ALL is lowest for people between the ages of 25 and 50. After age 50, the risk begins to increase.  According to the American Cancer Society (ACS), a 30-year-old person’s chance of developing ALL is 1 in 200,000. For a 70 year old person, the odds are 1 in 80,000.
  • Gender. The disease is slightly more common in males than in females.

Although acute lymphocytic leukemia is associated with these risk factors, most patients with the disease have no known risk factors.

Signs and symptoms of ALL

Acute lymphocytic leukemia (ALL) can cause a variety of signs and symptoms. Signs and symptoms usually appear as a decline in overall well being, including:

  • Weight loss
  • Fever
  • Loss of appetite
  • Weakness

Other signs and symptoms may develop from the reduction of normal red blood cells, white blood cells, and platelets caused by the disease. Anemia (an abnormally low amount of red blood cells) can trigger a variety of signs and symptoms including shortness of breath, fatigue, jaundice (yellow skin and eyes).

Individuals with ALL usually have a high white blood cell count. However, these white blood cells do not function normally and do not provide adequate protection against infection. As a result, infection or chronic illness may be a sign of the disease.

Thrombocytopenia (an abnormally low amount of platelets) can lower a patient’s ability to repair holes in damaged blood vessels. Signs and symptoms of thrombocytopenia include:

  • Excessive bruising or bleeding
  • Frequent or severe nosebleeds
  • Bleeding gums
  • Petechiae (pinpoint spots of blood under the skin)

ALL can also cause enlargement of the spleen (splenomegaly) and liver (hepatomegaly). Enlargement of these organs can result in a fullness or swelling of the abdomen.

Spread of ALL outside of the bone marrow to the organs, central nervous system, or other parts of the body can result in a variety of signs and symptoms depending on the area affected.

Signs and symptoms of ALL spreading to the central nervous system (brain and spinal cord) include:

  • Headaches
  • Weakness
  • Seizures
  • Vomiting
  • Difficulty maintaining balance
  • Blurred vision

Spread of ALL to the surface of the bone or into the joint can cause pain in these areas. If the disease has spread to the lymph nodes, it can cause the nodes to become enlarged (swollen glands), particularly in the neck or armpit.

The T-cell form of ALL often affects the thymus, which is a gland located in front of the windpipe and behind the breastbone. If the thymus becomes enlarged from the disease, it can cause coughing, shortness of breath or suffocation. 

Compression of the superior vena cava (the upper body’s main vein that returns blood to the right atrium of the heart from the upper half of the body) by leukemia cells can result in a condition known as SVC syndrome. A life-threatening condition, SVC syndrome can result in swelling of the head and arms.

Early symptoms of ALL may be overlooked because they may resemble symptoms of more common illnesses, such as influenza. Patients are encouraged to contact their physician when they experience any persistent symptom of ALL. The earlier the disease is diagnosed, the earlier treatment may begin and the better the prognosis.

Diagnosis methods for ALL

When physicians suspect that a patient may have acute lymphocytic leukemia (ALL), they will first obtain the patient’s medical history and perform a complete physical examination. During the physical examination, the physician may inspect the lymph nodes, spleen and liver for swelling.

A variety of tests may be used to diagnose, classify, and monitor the leukemia.  Samples of cells from the patient’s blood and bone marrow will be examined to verify the diagnosis. Tests will also be used to determine if the ALL has spread to the central nervous system (brain and spinal cord) or to other areas of the body. Additional tissue and cell samples may also be needed to guide treatment.

Common tests include:

  • Complete blood count and examination of blood cells under a microscope. A complete blood count (CBC) is a blood test that measures the number of red blood cells, white blood cells and platelets in a sample of blood. The test also measures the amount of hemoglobin in the red blood cells as well as other factors. Changes in the numbers of different blood cell types and the appearance of the cells can suggest leukemia. Patients with ALL usually have too many white blood cells and many of the cells will be lymphoblasts, an early form of lymphocyte. Many patients also have too few red blood cells and platelets.

  • Blood chemistry tests. These tests measure the level of specific chemicals in the blood. They are used to monitor changes in liver or kidney function caused by leukemia or treatment with certain chemotherapy drugs. The tests may be ordered to determine whether treatment is required to correct abnormally low or high levels of certain minerals.

  • Bone marrow tests. A bone marrow aspiration and biopsy may be ordered. A bone marrow aspiration involves administering a local anesthetic using a thin needle to collect a small sample of liquid bone marrow. A bone marrow biopsy uses a larger needle to remove a piece of bone marrow.  Usually performed at the same time, these procedures may be ordered to determine if leukemia is present or to monitor treatment.

  • Lumbar puncture. Also known as a spinal tap, this procedure uses a needle to remove a sample of cerebrospinal fluid (CSF) from between the bones in the lower spine. The sample is then examined for leukemia cells. The procedure may also be ordered to deliver chemotherapy drugs into the spinal fluid when leukemia cells are found there.

Additional tests include laboratory tests to diagnose and classify the leukemia, such as:

  • Routine microscopic exam. All samples (bone marrow, lymph node tissue, blood and CSF) are studied under a microscope by a pathologist. A number of characteristics, including the size and shape of the cells are noted in order to classify the cancer cells into specific types. The test may also be ordered to determine if a patient is in remission. The pathologist will examine the cells to determine if they appear mature (resembling normal cells) or immature (lacking the characteristic of normal cells).

    Blasts are the most immature type of cell. The amount of cells in the bone marrow that are blasts will be determined for diagnosis. A patient with ALL will have at least 20 to 30 percent blasts in the bone marrow. Following treatment, a patient must have a blast percentage of 5 percent or less to be considered in remission.

  • Cytochemistry. This test involves placing cells on glass microscope slides and exposing them to chemical stains. The stains then react with certain types of leukemia cells and change color. The color changes, or lack there of, are then detected under a microscope. The test may be ordered to distinguish one form of leukemia from another.

  • Flow cytometry. Fluorescent antibodies are used to detect certain molecules on the surface of leukemia cells. The cells being examined are treated with the antibodies, each of which attaches itself to certain types of molecules. The cells are then passed in front of a laser beam which causes the cells to give off light of a different color. The color is then measured and analyzed by a computer. This test may be ordered to determine the exact type of leukemia or to distinguish leukemia from other diseases. 

  • Cytogenetics.  The characteristics of cells, including their formation, function and structure, are evaluated under a microscope. Cytogenetic testing may be ordered to determine if the cells have too many chromosomes, or if the chromosomes have any translocations (the transfer of DNA from one chromosome to another). Identifying translocations helps to distinguish certain types of ALL and is important in determining the patient’s prognosis.

  • Immunocytochemistry (Immunophenotyping). This procedure uses special antibodies to detect certain molecules on the surface of leukemia cells. The cells being examined are treated with the antibodies, each of which attaches themselves to certain types of molecules. The cells containing these molecules then change color. The cells are then examined under a microscope. This test may be ordered to determine the exact type of leukemia or to distinguish leukemia from other diseases. 

  • Molecular genetic studies. These tests examine leukemia cell DNA. They may be ordered to detect translocations that are too small to detect under a microscope with cytogenic tests. Molecular genetic studies are useful in classifying ALL because many of its subtypes have distinctive translocations. Information about the translocations can also be used to predict the patient’s response to treatment. After treatment, the tests may be ordered to detect leukemia cells that can be missed under a microscope. 

ALL rarely forms visible tumors. For that reason, imaging tests have limited value. If imaging tests are done on patients with ALL, they are usually being conducted to diagnose infections or related problems rather than the leukemia. Imaging tests that may be ordered include:

  • Chest x-ray. This test uses low doses of radiation to produce images of the chest on film paper or fluorescent screens. It can reveal signs of a lung infection and detect enlarged lymph nodes in the chest.

  • Computed tomography (CT) scan. Also known as a computed axial tomography (CAT) scan, this test uses x-rays to take detailed cross-sectional images of the body from different angles around the patient. It also may be performed with contrast medium (dye) to more clearly define structures in the body. CAT scanning is helpful in detecting an accumulation of leukemia cells as well as enlarged lymph nodes or organs.
  • Magnetic resonance imaging (MRI). This test uses a powerful magnetic field to create images of structures and organs within the body, allowing a computer to produce very clear cross-sectional or three-dimensional images. It may be ordered to determine if the disease has spread to the spinal cord or brain. As with CAT scans, a contrast medium may be injected into the patient to help define structures.

  • Gallium scan and bone scan. In these procedures, a patient receives an injection of a slightly radioactive substance that is often absorbed by areas of the body where ALL is present or bone is damaged. The tests may be ordered when a patient has bone pain that may be due to ALL or an infection.

  • Ultrasound. This procedure uses high-frequency sound waves to produce images of internal organs. This test is useful for detecting enlarged kidneys, liver or spleen.

Treatment and prevention for ALL

As with all cancers, treatment for acute lymphocytic leukemia (ALL) is usually coordinated by a cancer care team, headed by a primary care physician and/or medical oncologist. For ALL, specialists may include a pediatrician, hematologist and radiation oncologist.

There are a variety of methods used to treat ALL. The exact treatment method chosen for each patient depends on the subtype of the leukemiaCertain prognostic factors also contribute to the treatment plan, including the patient’s age, white blood cell count, cytogenic test results and initial response to chemotherapy. Patients with ALL usually will be treated immediately and aggressively in order to destroy the cancer cells in the blood and bone marrow and put the leukemia in remission. Once signs and symptoms vanish, additional therapy may be given to prevent a relapse.

Since leukemia is a blood disorder and does not form tumors, surgery is not a form of treatment. Common treatment methods for ALL include:

  • Chemotherapy. This treatment method uses powerful drugs to destroy cancer cells. It may be used to prevent the cancer from spreading to the brain and spinal cord. When used to treat ALL, a combination of drugs is given to the patient over a long period of time. Chemotherapy is the most common treatment method for ALL.

  • Radiation therapy. Radiation therapy uses high-energy rays to destroy cancer cells and shrink tumors. It may be ordered to treat leukemia that has spread to the brain, spinal fluid or testicles. Radiation therapy may also be ordered before a patient undergoes a bone marrow or peripheral blood stem cell transplantation. On rare occasions, radiation treatment may be ordered as an emergency treatment to reduce the size of a mass pressing on the trachea.

  • Bone marrow/stem cell transplantation. This method allows a patient to receive high levels of chemotherapy, radiation or a combination of both. Although the high dose treatment destroys the leukemia cells, it also destroys normal blood cells in the bone marrow. After the treatment, the patient receives an infusion of healthy stem cells through a vein. The stem cells may come from a matched donor or from the patients themselves. As a result, new blood cells begin to develop from the transplanted cells. This procedure is still fairly new and complex and cannot be used with all patients.

Patients with ALL will be treated according to the severity of their cancer. Since ALL is a cancer of the blood, the treatments are designed to treat the entire body. Chemotherapy is the primary treatment and provided in the following stages:

  • Induction. This is the most aggressive stage. Its goal is to destroy as many cancer cells as possible and put the disease in remission. The patient usually receives a combination of chemotherapy drugs designed for the specific type of the disease.

  • Consolidation. During this phase, different drugs are given to destroy those cells that remain after the induction phase. This phase also focuses on preventing the spread of cancer cells to other areas, particularly the central nervous system (CNS). If cancer cells are noted in the spinal fluid at this time, the patient may also receive radiation therapy to the brain and spinal cord (part of the CNS).

  • Maintenance. This part of treatment is less intensive and may consist mainly of medications (pills) given at home. Occasionally, the patient may need to receive intravenous medications during this phase. The type of medication and dose will depend on the characteristics of the patient’s cancer. This phase of treatment may continue for about two years.

There are a number of terms that may be used to describe the status of ALL following treatment. These terms include:

  • Relapse. The return of cancer after the initial treatment is known as relapse. A patient with more than 5 percent blast cells present in the bone marrow may be classified as being in relapse.

  • Remission. Following treatment ALL may be classified as being in remission when:

    • The complete blood count is normal.

    • There are less than 5 percent blast cells in the bone marrow.

    • There are no signs or symptoms of the disease anywhere in the body.

  • Active disease. In a patient who is newly diagnosed or in relapse, ALL will be classified as an active disease.

  • Minimal residual disease. This term is used to describe a case of ALL when there is chemical evidence that cancer cells remain in the bone marrow, but there are not enough of the cells to be detected by routine examination under a microscope.

Patients may receive one method of treatment or a combination of treatments. After treatment, a patient may require regular visits to physicians for several years. Frequent checkups enable their physicians to detect any changes in health and treat them immediately. Checkups may include a physical examination, x-rays, blood tests, and other lab tests.

Patients are encouraged to report the development of any new symptoms to their physician. They may be a sign of recurrent ALL or side effects of treatment. If a relapse occurs, it typically occurs while patients are undergoing treatment, or shortly after they have completed chemotherapy. The disease can return in the blood, bone marrow, or other parts of the body. It is unusual for ALL to return if there are no signs of the disease five years after treatment.

The survival rate for patients with ALL has increased significantly since the 1970s, according to the American Cancer Society (ACS). From 1974 to 1978, the 5-year relative survival rate for an adult with ALL was 38 percent. From 1995 to 2001, that rate increased to 65 percent. For children under 15 years of age, the 5-year survival rate has increased to 87 percent. The improved survival rates are primarily due to advances in treatment of the disease.

Currently, there is no known method for preventing acute lymphocytic leukemia because it is not linked to preventable lifestyle risk factors.

Ongoing research regarding ALL

There is a great deal of research being conducted in the area of acute lymphocytic leukemia (ALL). Clinical trials and scientific studies are being conducted in cancer centers and laboratories by a number of medical groups. Areas of research for ALL include:

  • Imatinib. This drug has been designed specifically to damage cells that have the Philadelphia chromosome, a translocation that is found in some ALL patients. It works by preventing chemcial reactions that cause cells to grow and divide. In clinical trials, the drug has shown promising results for treatment of Philadelphia chromosome positive ALL. Clinical trials are currently being conducted to study the success of using imatinib alone and in combination with chemotherapy in treating various forms of leukemia.

    Researchers are studying two additional drugs that work as targeted therapies in ALL patients. These drugs, dasatinib and nilotinib, are being studied as treatment for ALL patients with the Philadelphia mutation. Clincial trials have suggested that these drugs may be beneficial for patients who are intolerant of or resistant to imatinib. 
  • Genetics. Researchers are trying to uncover how changes in a person’s DNA can cause normal bone marrow cells to develop into abnormal leukemia cells. Advances in cytogenetics are helping researchers analyze chromosome abnormalities for earlier detection and targeted treatment. Other techniques, such as gene expression profiling may help identify risk factors and plan targeted therapy.
  • Chemotherapy. New chemotherapy drugs are being studied. Other studies have focused on preventing leukemia cells from becoming resistant to chemotherapy, and determining the most effective combination of drugs. Researchers are trying to determine whether patients with poor prognosis benefit from more intensive chemotherapy. 
  • Monoclonal antibodies. These proteins are made in a laboratory and can be designed to attach to certain molecules on the surface of ALL cells. Radioactive chemicals or cell poisons can also be attached to the antibodies in an approach known as radioimmunotherapy.  When injected into a person with leukemia, the antibodies destroy the cancer cells. Several different monoclonal antibodies are currently being studied for use in the treatment of ALL.
  • Stem cell transplantation. Researchers are looking for ways to increase the effectiveness of stem cell transplantation, as well as reduce complications and determine which patients benefit most from the procedure.

Classifying ALL

Most types of cancer are classified by a process known as staging. Staging assigns numbered stages to cancers based on tumor size and how far the cancer spreads from the original site. Leukemia, however, is not staged because it involves all the bone marrow in the body and in many cases spreads to other organs. Instead, tests focus on establishing the type and subtype of leukemia. This information is then used to determine the prognosis (outlook) and predict which treatments will be most effective. Subtypes of ALL respond to treatment differently and their prognoses vary.

Acute lymphocytic leukemia (ALL) can be classified into subtypes based on cytogenic studies, flow cytometry and molecular genetic studies. These tests look for abnormalities in the genes and chromosomes of the cells. The cells are then further classified as either B-cells or T-cells.  Subtypes of ALL include:

  • Early pre-B ALL
  • Common ALL
  • Pre-B-cell ALL
  • Mature B-cell ALL (Burkitt leukemia)
  • Pre-T-cell ALL
  • Mature T-cell ALL

The classification of these subtypes is based on an older classification system known as the French-American-British (FAB) Classification of ALL. Based on the appearance of the cancer cells under a microscope (morphology), this system consists of three subtypes including:

  • L1. This subtype accounts for approximately 30 percent of ALL cases in adults, and involves T-cells or pre-B cells. In this type, the lymphoblasts are small cells.
  • L2. This subtype accounts for approximately 65 percent of ALL cases in adults, and involves T-cells or pre-B cells. In this type the lymphoblasts are larger.
  • L3. This subtype accounts for approximately 5 percent of ALL cases in adults, and involves B-cells. Also known as Burkitt type leukemia, this subtype has poor prognosis with standard therapy. The disease is very similar to Burkitt lymphoma, and as a result is treated differently than most leukemias.

Information provided by cytogenic studies, flow cytometry and molecular genetic studies also provides information for predicting prognosis. Among the most important information provided by these studies is information about translocations (the transfer of DNA from one chromosome to another). Translocations are the greatest factor in determining a patient’s prognosis. Patients with the Philadelphia chromosome (a translocation between chromosomes 9 and 22) have a much worse outlook than those without it. It occurs in between 20 and 25 percent of ALL patients. Occurring in 5 percent of ALL patients, a translocation between chromosomes 4 and 11 is another translocation that carries a poor prognosis.  

In addition to translocation information, certain prognostic factors have been identified to help a physician determine if a patient requires more or less treatment. The patient’s age, white blood cell count, cytogenic test results, and initial response to chemotherapy are all considered when determining whether a patient will respond well to treatment.

Adult ALL prognostic factors include:

  • Patients with T-cell ALL have the best prognosis, patients with mature B-cell ALL have the worst and those with pre-B-cell ALL have an intermediate prognosis.
  • Younger patients have a better prognosis.
  • Patients with an initial white blood cell count less than 50,000 have a better prognosis.
  • FAB L3 morphology predicts a worse prognosis.
  • Patients needing more than four to five weeks of therapy to reach complete remission have a worse prognosis.

Other factors that influence prognosis and treatment choices include:

  • Whether the ALL has spread to the brain or spinal cord
  • Whether the ALL has been treated before or has recurred

ALL is classified as a lymphocytic leukemia because it develops from bone marrow lymphocytes. Leukemias that develop from myeloid cells are known as myelogenous or myeloid leukemias. In some cases, however, the cancer cells have both lymphocytic and myeloid cell features on the same cell. In other patients, the leukemia may include some cells with myeloid characteristics and other cells with lymphocytic characteristics. These types of leukemias may be described as:

  • ALL with myeloid markers (My+ALL)
  • Acute myeloid leukemia (AML) with lymphoid markers
  • Biphenotypic (2-type) leukemias

Questions for your doctor about ALL

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients or parents may wish to ask their doctor the following questions about acute lymphocytic leukemia (ALL):

  1. What are the signs of ALL?
  2. How is ALL different from other forms of leukemia?
  3. What tests are used to diagnose the disease?
  4. When and from whom will I receive the results of the tests?
  5. What type of ALL do I have?
  6. What is my prognosis with this type of ALL?
  7. What are my treatment options for ALL?
  8. What are the risks associated with these treatments?
  9. If a bone marrow transplant is needed, how is a donor located?
  10. If my child needs a transplant, can I donate bone marrow?
  11. How will I know if I am in remission?
  12. What are the chances of ALL returning after remission?
  13. How will my condition be monitored after treatment?
  14. Are my children at higher risk for leukemia if I have ALL?
  15. Does ALL place me at risk for other cancers?
  16. Can you recommend a support group?
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