Acute Lymphocytic Leukemia (ALL)

Definition

Acute lymphocytic leukemia is a progressive, malignant disease characterized by large numbers of immature white blood cells that resemble lymphoblasts. These cells can be found in the blood, the bone marrow, the lymph nodes, the spleen, and other organs.

Bone marrow aspiration
Acute lymphocytic leukemia - photomicrograph
Auer rods
Bone marrow from hip
Immune system structures

Alternative Names

Causes, incidence, and risk factors

Acute lymphocytic leukemia (ALL) accounts for 80% of the acute leukemias of childhood, with most cases occurring between ages 3 and 7. ALL also occurs in adults, where it accounts for 20% of all adult leukemias.

In acute leukemia, the malignant (cancerous) cell loses its ability to mature and specialize (differentiate) its function. These cells multiply rapidly and replace the normal cells. Bone marrow failure occurs as malignant cells replace normal bone marrow elements. The person becomes susceptible to bleeding and infection because the normal blood cells are reduced in number.

Most cases seem to have no apparent cause. However, radiation, some toxins such as benzene, and some chemotherapy agents are thought to contribute to brining on leukemia. Abnormalities in chromosomes may also play a role in the development of acute leukemia.

Risk factors for acute leukemia include Down syndrome, a sibling with leukemia, and exposure to radiation, chemicals, and drugs. The disease strikes 6 out of every 100,000 people.

Symptoms

• Prolonged or excessive bleeding, bruising easily
• Bleeding gums
• Nosebleeds
• Bleeding into the skin
• Menstrual irregularities
• Skin rash or lesion
  • Pinpoint red spots (petechiae)
  • Bruises (ecchymoses )
• Paleness
• Fatigue
• Infection
• Sternal tenderness
• Bone pain or tenderness
  • Breastbone (sternum)
• Joint pain
  • Hip pain
  • Knee pain
  • Ankle pain
  • Foot pain over small joints of the foot
  • Shoulder pain
  • Elbow pain
  • Wrist pain
  • Hand pain over small joints of the hand
• Lymphadenopathy (enlarged glands)
• Unintentional weight loss
• Fever
• Swollen gums
• Shortness of breath (made worse by exercise)
• Sensations of feeling the heart beat (palpitations ) with an irregular pattern

Signs and tests

A physical exam and lab tests may reveal the following:

• Enlarged liver and spleen
• Bruising (ecchymosis)
• Evidence of bleeding (petechiae, purpura)
• Abnormal WBC count
• A CBC shows anemia
• Low platelet count
• A bone marrow aspiration shows an increased number of cells (hypercellularity) and an increase in lymphoblasts.

ALL may also alter the results of the following tests:

• T (thymus derived) lymphocyte count
• Cell surface antigen studies (B-cell, leukemia/lymphoma panel)
• White blood cell differential

Classification of ALL now depends on a number of sophisticated tests, such as immunophenotyping, karyotyping, and terminal deoxynucleotidyltransferase (TdT) activity. The combined results of these tests allow pinpoint molecular diagnosis, which helps guide the treatment decisions, and clarify the likely prognosis.

For instance, the cells of some leukemias contain chromosomal abnormalities. Those with the Philadelphia chromosome or with the t(4;11) translocation would tend to have a poor prognosis, thus intensive treatment and an early bone marrow transplant might be recommended immediately. Other genes (such as the TEL/AML1 rearrangement) can indicate a very favorable prognosis.

Treatment

The goal of treatment is remission of the cancer. A remission is achieved when the peripheral blood counts and the bone marrow are normal.

Acute lymphocytic leukemia is treated with a combination of anti-cancer drugs (chemotherapy). A hospitalization of 3 to 6 weeks may be necessary for initial (induction) chemotherapy, however, subsequent chemotherapy sessions may be given on an outpatient basis. Additionally, the patient may need to be isolated if the lymphocyte count is very low to prevent catching an infection.

Chemotherapy typically consists of a combination of 3 to 8 medications which may include: prednisone, vincristine, methotrexate, 6-mercaptopurine, and cyclophosphamide. It may also be necessary to administer blood products (e.g., packed red blood cells, platelets ) to treat the anemia and low platelet count. Antibiotic therapy may be required to treat any secondary infections that develop.

After remission is achieved, chemotherapy or radiation therapy may be given in the spinal column to treat any leukemia cells that may have invaded the spinal fluid.

Subsequent therapy is meant to prevent relapse and consists of additional chemotherapy given intermittently, either in the hospital or as an outpatient. This treatment may last up to one year. A bone marrow transplant after high-dose chemotherapy may be a treatment option for cases that relapse or do not respond to other treatments.

Support Groups

The stress of illness can often be helped by joining a support group where members share common experiences and problems. See cancer - support group and leukemia - support group.

Expectations (prognosis)

The probable outcome for children is better than for adults, with an 80% cure rate. Eighty percent of adults achieve complete remission, with 30% to 50% being cured. Without treatment, the life expectancy is about 3 months.

Complications

• DIC (disseminated intravascular coagulation)
• Relapse of ALL
• Severe infection

Calling your health care provider

Call for an appointment with your health care provider if symptoms suggestive of ALL develop.

Call your health care provider if persistent fever or other signs of infection occur in a person with ALL.

Prevention

Because the cause of most cases is unknown, prevention of most cases is not possible. Minimizing exposure to toxins, radiation, chemicals, etc. may reduce risk.

---

Review Date:7/29/2005
Reviewed By: William Matsui, M.D., Assistant Professor of Oncology, Division of Hematologic Malignancies, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD. Review provided by VeriMed Healthcare Network.