Acute lymphocytic leukemia, or acute lymphoblastic leukemia (ALL), is a cancer that affects the bone marrow and blood. Doctors categorize ALL into risk groups to determine the most effective treatment plan for the disease.
Of all the risk groups, standard risk ALL carries the most favorable prognosis. However, the outcome for all risk groups continues to improve with the advancement of new treatments.
This article defines ALL, including its causes and risk factors. We then discuss the criteria for the different ALL risk groups and outline the treatment and prognosis for standard risk ALL.
Leukemia is a type of cancer that develops in blood-forming cells within the bone marrow. These atypical cells do not function in the way that healthy cells work.
An accumulation of atypical cells within the bone marrow and blood makes it difficult for the healthy cells to function properly. This makes a person susceptible to infection and illness.
ALL affects a type of white blood cell called lymphocytes. Ordinarily, lymphocytes help the body fight infections and disease, but in ALL, the lymphocytes become atypical and do not function properly. They quickly outnumber the healthy lymphocytes, making a person susceptible to infection and illness.
The term “acute” in ALL indicates that the disease is rapidly developing and can worsen very quickly without treatment.
Causes of ALL
ALL develops as a result of DNA changes in the bone marrow cells. However, doctors cannot always identify the cause of these changes.
According to the
- Down syndrome
- Li-Fraumeni syndrome
- Fanconi anemia
Risk factors for ALL
Some factors that may increase a person’s risk of developing ALL
- Age: The disease is more common in children and in adults aged 50 years and older.
- Gender: The disease occurs mostly in males.
- Ethnicity: ALL more commonly occurs among white people than African Americans.
- Genetic conditions: The genetic conditions Klinefelter syndrome and Fanconi anemia can increase the risk of ALL.
Other risk factors for ALL include:
- previous chemotherapy treatment
- radiation therapy
- exposure to the substance benzene
- weakened immunity due to HIV or medications that suppress immunity following an organ transplant
About B-cell ALL
B-cell ALL or precursor B-lymphoblastic leukemia is the
B-cells make proteins called antibodies, which attach themselves to bacteria, viruses, and fungi. This process signals the immune system to target and destroy these pathogens. In B-cell ALL, the B-cell lymphoblasts are defective.
A person with B-cell ALL may experience any of the following symptoms:
Medical professionals categorize ALL into one of three risk groups to help determine the most effective treatment for the disease.
- Standard or low risk: This group includes children between the ages of 1 and 9 years whose white blood cell count is less than 50,000 per microliter (mcl) of blood at the time of diagnosis.
- High risk: This group includes people aged 10 years and older or those who have with a white blood cell count of 50,000 mcl or more at the time of diagnosis.
- Very high risk: This group includes children who:
- are under 1 year of age
- have certain genetic changes
- do not respond immediately to treatment
- show signs of leukemia 4 weeks after receiving their first treatment
The Leukemia & Lymphoma Society lists the tests that help doctors provide a diagnosis for ALL. These include:
- A complete blood count: A blood sample that checks the number of red and white blood cells and platelets. It also checks the different types of white blood cells in the sample. People with ALL have a low number of white blood cells, red blood cells, and platelets.
- Bone marrow aspiration and biopsy: Bone marrow aspiration is a procedure that involves using a thin needle to remove a small sample of liquid bone marrow. A bone marrow biopsy involves taking a small sample of the bone, which contains the marrow. Doctors perform these procedures at the same time, administering local anesthesia to numb the area.
- Cell assessment: A hematopathologist examines the blood or bone marrow sample and records the following:
- cell type, size, and shape
- whether the sample contains mature or immature cells
- whether the cells appear typical or atypical
This section explains how doctors treat standard risk ALL in children.
According to the NCI, there are
Remission induction is the first phase of cancer treatment for standard risk ALL. It involves killing leukemia cells in the bone marrow and blood. The goal of this phase is to achieve remission, where there are no detectable leukemia cells in the bone marrow. Blood counts should also return to expected levels in remission.
Treatment involves a combination of the chemotherapy agents L-asparaginase and vincristine and the steroid dexamethasone. Doctors may also prescribe antibiotics to prevent or treat bacterial infections.
People may also receive intrathecal chemotherapy, which involves administering a chemotherapy agent directly into the cerebrospinal fluid. This can help treat cancer that has spread to the brain and spinal cord or cancer that is at risk of spreading to these areas.
The first month of treatment can be intense. People may need to stay in the hospital for long periods to reduce the risk of infections and complications.
Consolidation or intensification
The consolidation or intensification phase aims to destroy any leukemia cells that remain after a person has achieved remission. This phase consists of intensive chemotherapy treatment lasting up to 9 months.
Treatment typically consists of a combination of chemotherapy medications. Using multiple drugs helps prevent the leukemia cells from developing resistance to a particular medication.
People with standard risk ALL may receive the following drugs:
- 6-mercaptopurine (6-MP)
The goal of maintenance therapy is to remove the remaining leukemia cells that may have a chance to regrow. Individuals may receive lower medication doses than they received during the previous two phases. They typically receive the treatment with an outpatient procedure.
According to the
People who do not take their medication may be at
According to the ACS, factors that affect prognosis include:
- Initial white blood cell (WBC) count: Children with WBCs below 50,000 mcl at diagnosis have a better prognosis than those whose WBCs exceed this figure.
- Age: The prognosis is better for children aged 1–9 years at the time of diagnosis, compared with those aged 10 years or older.
- Sex: Cure rates appear slightly higher among girls than boys. However, this difference is diminishing due to recent improvements in ALL treatments.
- Initial treatment response: Children whose ALL enters remission within 1–2 weeks of induction therapy tend to have a better outlook.
- Chromosome changes: A “translocation” is the scientific term for when chromosomes swap some of their DNA. A child is more likely to be cured of ALL if the leukemia cells involve a translocation between chromosomes 12 and 21 compared with a translocation between chromosomes 4 and 11.
ALL is an aggressive form of cancer that affects white blood cells called lymphocytes. The disease is more common among children and people over 50 years of age.
Doctors classify ALL into one of three risk groups to determine the most effective treatment for the disease. These groups are standard risk, high risk, and very high risk ALL. Standard risk ALL carries the most favorable prognosis. This group includes children between the ages of 1 and 9 years with a white blood cell count of less than 50,000 mcl at the time of diagnosis.
As with other ALL risk groups, the treatment for standard risk ALL consists of three phases: induction, consolidation, and maintenance. Each phase involves a combination of chemotherapy medications to help destroy the cancer cells. The overall aim of treatment is to achieve and maintain disease remission.