Acute lymphoblastic leukemia (ALL) is a type of blood cancer. Also known as acute lymphocytic leukemia or acute lymphoid leukemia, it is the least common type of leukemia in adults. Here's what you need to know about symptoms, prognosis, survival rates, and treatment for ALL.
What Is Acute Lymphoblastic Leukemia?
ALL is a type of leukemia that starts from white blood cells in the bone marrow, the soft inner part of bones. It develops from cells called lymphocytes, a type of white blood cell central to the immune system, or from lymphoblasts, an immature type of lymphocyte.
Acute lymphoblastic leukemia invades the blood and can spread throughout the body to other organs, such as the liver, spleen, and lymph nodes. But it does not normally produce tumors as do many types of cancer. It is an acute type of leukemia, which means it can progress quickly. Without treatment, it can be fatal within a few months.
The outlook for acute lymphoblastic leukemia depends on factors such as:
- Your age: Younger patients tend to have a better outlook.
- Your lab test results: The prognosis is better if you have a lower white blood count when you're diagnosed.
- Your subtype of ALL (B-cell ALL or T-cell ALL)
- Whether you have a chromosome abnormality called the Philadelphia chromosome; having it suggests a poorer prognosis.
- Your response to chemotherapy: The prognosis is better if you have no evidence of leukemia four to five weeks after starting treatment.
Risk Factors for Acute Lymphoblastic Leukemia
For most people, the cause of ALL is unknown. For this reason, there is no known way to prevent it. However, there are a few known risk factors for this type of leukemia. This means these factors may increase your chances of getting acute lymphoblastic leukemia. But it is not yet known whether these risk factors are actual causes of the disease:
- Exposure to high levels of radiation to treat other types of cancer
- Exposure to certain chemicals such as benzene, a solvent used in oil refineries and other industries and present in cigarette smoke, certain cleaning products, detergents, and paint strippers
- Infection with human T-cell lymphoma/leukemia virus-1 (HTLV-1) in rarer cases outside the U.S., or Epstein-Barr virus (EBV), a related leukemia more commonly seen in Africa
- Having an inherited genetic syndrome such as Down syndrome
- Being white
- Being male
Symptoms of Acute Lymphoblastic Leukemia
Treatment for Acute Lymphoblastic Leukemia
ALL is really a group of related diseases, or subtypes. Therefore, your treatment options depend upon your subtype and other factors. You may have more than one type of treatment. These include:
- Chemotherapy, the use of anticancer drugs in combination, generally over a couple of years. Agents used for ALL include:
- Targeted therapy, drugs that target specific parts of cancer cells and tend to have fewer or less severe side effects than chemotherapy; examples include imatinib (Gleevec), dasatinib (Sprycel), blinatumomab (Blincyto), ponatinib (Iclusig), and nilotinib (Tasigna), which attack cells with the Philadelphia chromosome.
- Radiation therapy, the use of high-energy radiation to kill cancer cells; this is not used often for ALL, but may be used to treat leukemia in the brain or bone, for example, or before a stem cell transplant.
- A bone marrow transplant, which involves use of high doses of chemotherapy and possibly radiation followed by a transplant of bone-forming stem cells; stem cells usually come from a donor, or less likely, from your own bone marrow or peripheral blood. If you cannot tolerate high doses of chemotherapy and radiation, lower doses may be used with a "mini-transplant."
Treatment occurs in two parts -- induction therapy and post-induction therapy.
The goal of induction therapy is to achieve remission by:
- Killing as many leukemia cells as possible
- Returning blood counts to normal
- Ridding the body of signs of disease for a long time
About eight or nine out of 10 adults achieve remission after treatments, but many relapse, which lowers the overall cure rate to 30% to 40%. So even with remission, post-induction therapy is needed to prevent relapse. It involves cycles of treatment over two to three years. Usually, the drugs are different than the drugs used in induction therapy. The goal is to completely rid the body of leukemia cells that have not been found by common blood or marrow tests.