Acute lymphoblastic leukemia (ALL) is a type of leukemia that primarily affects children, although it can also affect adults. It is also called acute lymphoblastic leukemia or acute lymphoblastic leukemia. ALL affects immature lymphocytes (a type of white blood cell) called blasts.
ALL is actually the most common cancer in children, accounting for about 25% of childhood cancers. In the United States, more than 5,000 people develop ALL each year, and approximately 1,500 people die, although more than 75% of those who die are adults.
The disease progresses fairly rapidly and is characterized by large numbers of immature white blood cells in the blood and bone marrow. While in the past it was a rapidly fatal disease, it is now largely survivable with chemotherapy.
The description that cancer is simultaneously aggressive and survivable may confuse some people. Chemotherapy works by attacking the fastest dividing cells, so aggressive cancers respond better to chemotherapy than slower-growing cancers. Although this cancer mainly occurs in children, children often do better than adults with the disease.
What are lymphoblasts?
A lymphoblast is an immature type of white blood cell called a lymphocyte. In the bone marrow, a process called hematopoiesis takes place, which basically means the formation of our immune cells and blood cells.
The process begins with hematopoietic stem cells, which can evolve along the myeloid lineage (which then becomes a type of white blood cell called a granulocyte, red blood cell, or platelet) or the lymphatic lineage. Lymphoblasts are the “babies” in this process. Lymphoblasts can go on to become T lymphocytes (T cells), B lymphocytes (B cells), or natural killer cells (NK cells).
The exact cause of ALL is not known, but risk factors may include:
- Some genetic diseases, such as Down syndrome and Klinefelter syndrome
- Exposure to substances such as benzene
- Prenatal exposure to X-rays
- exposure to cancer treatment, including radiation therapy and chemotherapy
- some chromosomal changes or gene mutations
Because lymphoblasts are produced in the bone marrow, all types of blood cells—including white blood cells, red blood cells, and platelets—are affected. The white blood cells produced — even in higher-than-normal numbers — don’t function as they normally would, and the number of other forms of blood cells usually decreases.
Symptoms may include:
- fatigue and weakness
- pale (pale skin)
- fever or night sweats
- Frequent infections (this is difficult to identify in children who are usually infected several times a year)
- easy bruising and/or bleeding
- shortness of breath
- decreased appetite and weight loss
- Petechiae (spots of skin that appear red and don’t go away when pressure is applied to the skin)
- Bone and joint pain, especially long bones
- Painless swollen lymph nodes in the neck, armpits, and groin
- Upper abdominal tenderness due to an enlarged liver or spleen
ALL is usually first suspected on the basis of increased white blood cell counts and increased numbers of immature lymphocytes. Further tests performed during diagnosis may include:
- more blood tests
- Bone marrow aspiration and biopsy
- Imaging tests, such as computed tomography or magnetic resonance imaging, to look for tumors, especially those in the abdomen, chest, or spinal cord
- Lumbar puncture (spinal tap) to look for cancer cells in the cerebrospinal fluid
Unlike some cancers, chemotherapy for ALL is usually done in years, not weeks.
Treatment for ALL can be divided into the following stages, but usually includes intensive chemotherapy (stem cell transplantation and radiation therapy are sometimes part of the treatment):
- Remission induction: After a diagnosis of ALL, the first step is to reduce the number of blasts and restore normal cell production in the bone marrow. This involves aggressive chemotherapy, sometimes as an inpatient. After this step, people with ALL are usually in remission.
- Remission consolidation: The next step is to take care of any cancer cells that survive induction therapy.
- Maintenance therapy: Even if this cancer is in remission and further treatment has eliminated any lingering cancer cells, it can recur without further treatment. Maintenance therapy is designed to prevent the leukemia from returning and lead to long-term survival, which may last two to three years.
- Central Nervous System (CNS) Prevention: If ALL is present in the cerebrospinal fluid, intrathecal chemotherapy is usually given because most chemotherapy drugs do not cross the blood-brain barrier. For many patients without CNS involvement, treatment (which may also include radiation therapy) is given to prevent cancer from developing or returning in the brain.
Children with ALL have a slightly better prognosis than adults. About 98% of children are in remission, and about 85% go on to survive long-term.
support and response
In most cases, this is a child who is going through ALL, so support needs to be provided not only for the child with ALL, but also for their parents. Learn as much as you can about the disease. Reach out. Leukemia treatment is a marathon not a sprint, and it helps some of those who help know that you don’t need it right away, but please help over time.
Support for children with cancer has improved significantly, and there are now children’s camps across the country dealing with the disease. These camps help kids feel like they’re not missing out on what their cancer-free peers are enjoying.