Acute lymphoblastic leukaemia (ALL), also known as acute lymphocytic leukaemia, is a type of leukaemia (cancer of blood/blood forming tissue) that causes an overproduction of immature white blood cells, also known as lymphoblasts or leukaemic blasts.
Blood is the bodily fluid of the circulatory system that provides nutrients and oxygen to our tissues, and helps to remove waste from our bodies. There are three primary types of blood cells produced in the inner, spongy portion of the bone (bone marrow) from stem cells (immature blood cells that develop into either red blood cells (RBCs), white blood cells (WBCs), or platelets). RBCs, or erythrocytes, are responsible for providing oxygen to the tissues in our body, as well as transporting carbon dioxide to the lungs to be exhaled. WBCs are responsible for fighting infection and disease in the body. Platelets are blood cells that play a major role in blood clotting (or coagulation), which is an important process that helps reduce blood loss after injury.
ALL causes excess immature WBCs to be produced, which reduces the capacity of the bone marrow to produce RBCs, healthy WBCs, and platelets.
ALL is the most common form of childhood leukaemia. It is more common in males, and is generally diagnosed in children under 14 years of age. However, anyone can develop this disease.
Types of Acute Lymphoblastic Leukaemia
There are several different types of ALL, which are categorised by the types of cells they originate from.
Pre-B-cell ALL
Pre-B cell ALL, also known as precursor B-cell ALL, is the most common type of ALL, and causes excess production of immature (or precursor) B cells (a type of WBC) in the bone marrow. This type of ALL is often aggressive, and may metastasise. In children, the prognosis for this disease is often good when caught early. However, adults with pre-B cell ALL may not have as good of a prognosis.
B-cell ALL
B-cell ALL, also known as Burkitt-like or Burkitt type ALL, is the least common type of ALL that develops from maturing B cells in the bone marrow. This type of ALL is often aggressive, and may metastasise. Both adults and children with this disease can have a good prognosis when caught early.
T-cell ALL
T-cell ALL is a less common type of ALL that develops from developing T-cells (a type of WBC) in the bone marrow. This subtype is often aggressive, and may metastasise. In children, the prognosis for this disease is often good when caught early. However, adults with T-cell ALL may not have as good of a prognosis.
Treatment
Staging and Grading of ALL
When cancers are detected, they are staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you. However, because of how rare ALLs are, there is currently no standard staging and grading system for this disease. Instead of staging and grading, your doctor will recommend a treatment plan based on the following factors:
- The type of ALL you have.
- Whether or not the cancer has metastasised.
- Your age.
- General health.
- Your treatment preferences.
Your doctor may also recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Phases of Treatment
Treatment for ALL in both children and adults are generally done in phases:
Phase 1: Remission Induction Therapy
Remission induction therapy is an intensive course of treatment aimed at inducing disease remission. For this phase, the patient is admitted to hospital. In some cases, the disease won’t respond to treatment as expected, and it may be said that the patient has a resistant or refractory disease. In these cases, the doctor may recommend a more intensive form of therapy to treat the disease more effectively.
Phase 2: Post-remission (Consolidation) Therapy
After remission is achieved, post-remission or consolidation therapy is used to help destroy any remaining cancer cells left in the body. This phase is crucial for ensuring the cancer does not return (or relapse), and that it does not spread into the central nervous system (CNS) (the system responsible for all sensory and motor functions in the body that is composed of the brain and the spinal cord). The intensity of this phase depends on how well the patient responds to phase one of treatment.
Phase 3: Maintenance Therapy
Maintenance therapy is the final phase of treatment, and is designed to keep the patient’s disease in remission, and to prevent it from relapsing. This phase generally lasts for several months, and the patient is generally treated as an outpatient; however, in some cases they may need to be admitted into hospital.
Treatment Options
Treatment is dependent on several factors, including age, stage of disease and overall health.
Treatment options for ALLs in both children and adults may include:
- Chemotherapy.
- Cortio-steroid therapy.
- Radiation therapy.
- Stem cell transplant.
- Targeted therapy.
- Immunotherapy, potentially including CAR T-cell therapy.
- Clinical trials.
- Palliative care.
For more information on the treatment options, please refer to the Rare Cancers Australia treatment options page.
Risk factors
While the cause of ALL remains unknown, the following factors may increase the likelihood of developing the disease:
- Genetic mutations of genes involving blood cell development.
- Prior exposure to radiation and/or chemotherapy.
- Being exposed to x-rays before birth.
- Having certain genetic conditions, such as:
- Exposure to industrial chemicals, potentially including:
- Being exposed to certain viral infections.
- Having an identical twin who develops ALL within the first year of life.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Early symptoms
Symptoms of ALL are similar between adult and paediatric subtypes.
In the early stages of disease, some patients may appear symptomatic. As the cancer progresses, some of the following symptoms may appear:
- Anaemia, which carries its own set of symptoms:
- Fatigue.
- Dizziness.
- Paleness.
- Shortness of breath.
- Frequent or persistent infections.
- Easy bruising and/or bleeding.
- Bone and/or joint pain.
- Swollen lymph nodes (painless lumps) in the neck, underarms, stomach, and/or groin.
- Abdominal discomfort, potentially caused by a swollen liver, thymus, and/or spleen.
- Purpura or petechiae (a rash of small, red dots due to small superficial capillary bleeds).
- Unexplainable weight loss and/or loss of appetite.
- Fever and/or drenching night sweats.
- Heavy menstrual periods.
Not everyone with the symptoms above will have cancer, but see your GP if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have an ALL, they will order a range of diagnostic tests to confirm the diagnosis, and refer you to a specialist for treatment.
Physical examination
Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities.
Blood tests
Blood tests are used to assess overall health and detect any abnormalities. Some of these tests may include:
- General blood test to assess overall health.
- Full blood count, which measures the levels of red blood cells, white blood cells and platelets.
- Blood chemistry and/or blood hormone studies, which analyse the levels of certain hormones and other substances in the blood.
- Blood smears to check changes in the number, type, shape, and size of blood cells for too much iron in RBCs.
Imaging tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), x-rays, ultrasounds, bone scans and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and look for signs of metastasis.
Lumbar Puncture
A lumbar puncture, or spinal tap, involves inserting a needle between two vertebrae in the lower spine and extracting a sample of cerebrospinal fluid (CSF) for analysis. A local anaesthetic or sedative is given prior to the procedure. Your doctor will discuss any risks and possible complications with you prior to the procedure.
Bone Marrow Aspiration & Biopsy
This process involves inserting the needle into the hipbone (or the breastbone in some cases) to remove samples of solid and liquid bone marrow. These samples will then be analysed for abnormalities.
Once the location(s) of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. The tissue sample will then be analysed for cancer cells. This can be done by a fine needle aspiration (FNA), a core needle biopsy (CNB), or a trephine biopsy (removal of a small portion of bone for analysis).
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage ALLs and childhood ALLs have a better prognosis and survival rates. However, if the cancer is advanced and has spread, or is found in adulthood, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.