Understanding Acute Lymphoblastic Leukemia
Acute lymphoblastic leukemia (ALL), also called acute lymphocytic leukemia, is a rapidly progressing cancer of the blood and bone marrow. It develops when immature lymphoid cells, known as lymphoblasts, multiply abnormally and interfere with the production of healthy blood cells.
ALL can occur at any age, but it is particularly common in children. Modern treatment has significantly improved outcomes, especially for children, although the prognosis and treatment approach can vary considerably depending on age, disease subtype, genetic characteristics and response to therapy.
What is Acute Lymphoblastic Leukemia?
Bone marrow is the soft tissue inside many bones where blood cells are produced. Normally, blood-forming cells develop into healthy red blood cells, platelets and different types of white blood cells.
In ALL, immature lymphoid cells begin growing uncontrollably. These abnormal cells accumulate in the bone marrow and blood, leaving less room for healthy blood-cell production. As a result, people with ALL may develop anemia, infections or bleeding problems. The leukemia can also involve areas outside the bone marrow, including the lymph nodes, spleen, liver and central nervous system.
The word “acute” is important because ALL can progress quickly if it is not treated.
Who Can Develop ALL?
ALL can affect both children and adults. It is the most common type of cancer diagnosed in children, with the highest occurrence in early childhood.
However, adults can also develop ALL, and treatment outcomes tend to differ between children and adults.
Types of Acute Lymphoblastic Leukemia:
ALL is broadly classified according to the type of lymphoid cell from which the leukemia develops.
- B-Cell ALL: B-cell acute lymphoblastic leukemia develops from abnormal immature B-cell precursors. It represents the majority of ALL cases and is particularly common among children.
- T-Cell ALL: T-cell acute lymphoblastic leukemia develops from immature T-cell precursors. It is less common than B-cell ALL and can have different clinical and biological characteristics.
Doctors may also classify ALL according to its genetic and molecular features. These characteristics can influence the expected behavior of the disease and help the medical team select an appropriate treatment strategy.
Symptoms of Acute Lymphoblastic Leukemia:
ALL can affect the body's normal blood-cell production, so symptoms may develop because of low levels of healthy blood cells or because leukemia cells accumulate in other tissues.
Possible symptoms include:
- Persistent tiredness or weakness
- Fever or night sweats
- Frequent or repeated infections
- Easy bruising
- Unusual bleeding
- Tiny red or purple spots on the skin
- Pale skin
- Shortness of breath
- Bone or joint pain
- Swollen lymph nodes
- Reduced appetite
- Unexplained weight loss
- Abdominal discomfort or swelling
These symptoms are not specific to ALL and can occur with many other conditions. However, persistent or unexplained symptoms should be evaluated by a healthcare professional.
What Causes Acute Lymphoblastic Leukemia?
ALL develops because of genetic changes in blood-forming cells. These changes interfere with normal cell development and allow immature lymphoid cells to multiply uncontrollably.
In many people, it is not possible to identify one specific event that caused these genetic changes.
Some factors are associated with an increased risk of ALL, including certain inherited genetic conditions and previous exposure to radiation or some cancer treatments. However, having a risk factor does not mean that someone will definitely develop leukemia.
Importantly, most people who develop ALL do not have an obvious preventable cause.
Risk Factors for ALL:
Factors that may be associated with ALL include:
- Age: ALL is particularly common in young children, although it can occur throughout life.
- Certain Genetic Conditions: Some inherited conditions, including Down syndrome, are associated with an increased risk of childhood ALL.
- Previous Cancer Treatment: Certain chemotherapy treatments and radiation exposure can increase the risk of developing leukemia later in life.
- Previous Radiation Exposure: Significant exposure to ionizing radiation can increase leukemia risk.
It is important to remember that these factors explain only a proportion of cases. ALL can occur in people without any identifiable risk factor.
Possible Complications of ALL:
Without effective treatment, leukemia cells can interfere substantially with normal blood-cell production and may spread beyond the bone marrow.
Potential complications include:
- Severe anemia
- Serious infections
- Excessive bleeding
- Bone or joint discomfort
- Enlargement of the liver or spleen
- Enlarged lymph nodes
- Involvement of the central nervous system
- Treatment-related complications
When leukemia involves the brain or spinal cord, symptoms may include headaches, vomiting, vision changes, weakness, balance problems or seizures.
Because the central nervous system can act as a site where leukemia cells are difficult for some medicines to reach, ALL treatment commonly includes therapy specifically designed to prevent or treat disease in this area.
How is Acute Lymphoblastic Leukemia Diagnosed?
A doctor may begin with a physical examination and a review of symptoms and medical history.
- Blood Tests: A complete blood count and examination of blood cells can identify abnormalities in red cells, white cells and platelets and may reveal abnormal lymphoblasts.
- Bone Marrow Examination: A bone marrow aspiration and/or biopsy is an important part of confirming the diagnosis and determining the characteristics of the leukemia.
- Immunophenotyping: Laboratory testing can examine proteins on the surface of leukemia cells. This helps determine whether the disease is associated with B-cell or T-cell development.
- Genetic and Molecular Testing: Chromosomal and molecular tests can identify genetic changes within leukemia cells. These findings can be important for determining risk and selecting targeted treatments.
- Additional Testing: Depending on the individual situation, doctors may evaluate the cerebrospinal fluid to determine whether leukemia has reached the central nervous system. Imaging and other investigations may also be performed when clinically appropriate.
There is no conventional stage 1-to-4 system for ALL. Instead, doctors describe the disease according to factors such as whether it is newly diagnosed, in remission or recurrent, along with its biological and risk characteristics.
Treatment of Acute Lymphoblastic Leukemia:
ALL requires treatment by a specialist hematology/oncology team. The treatment plan is individualized according to factors such as:
- Age
- B-cell or T-cell subtype
- Genetic characteristics
- White blood cell count at diagnosis
- Central nervous system involvement
- Response to initial treatment
- Whether the disease is newly diagnosed or has returned
Treatment may involve one or several approaches.
Chemotherapy: Chemotherapy remains a major component of ALL treatment. This treatment is generally organized into different phases designed to first achieve remission and then eliminate remaining leukemia cells and reduce the risk of recurrence.
For childhood ALL, these phases commonly include:
- Remission induction → Consolidation/intensification → Maintenance
Treatment may extend over a prolonged period, depending on the patient's specific protocol and risk category.
Central Nervous System-Directed Treatment: Because leukemia cells can enter the brain and spinal cord, treatment often includes therapy directed toward the central nervous system.
This can include chemotherapy delivered directly into the cerebrospinal fluid, known as intrathecal chemotherapy, along with systemic treatment. Radiation may be considered in selected circumstances.
Targeted Therapy: Some forms of ALL contain specific genetic abnormalities that can be targeted with medicines. For example, people with Philadelphia chromosome-positive ALL may receive a tyrosine kinase inhibitor (TKI) alongside other treatments. Medicines used in this setting can include imatinib, dasatinib or other appropriate TKIs depending on the clinical situation.
Immunotherapy: Immunotherapy uses the body's immune system, or specially designed immune-based approaches, to recognize and attack leukemia cells.
Depending on the disease setting, treatment may include medicines such as blinatumomab or inotuzumab ozogamicin, while some patients may be considered for CAR T-cell therapy. Availability and eligibility depend on the patient's disease characteristics, treatment history and local regulatory approvals.
Stem Cell Transplant: An allogeneic stem cell transplant, sometimes called a bone marrow transplant, may be considered for selected patients, particularly in certain high-risk or relapsed/refractory situations.
It is a complex treatment with potentially significant risks, so the decision requires careful assessment by a specialist transplant team.
Treatment for Relapsed or Refractory ALL: Sometimes ALL does not respond adequately to initial therapy (refractory ALL) or returns after a period of remission (relapsed ALL).
Treatment options can include different chemotherapy combinations, targeted medicines, immunotherapy, CAR T-cell therapy and/or stem cell transplantation, depending on the patient's age, leukemia subtype, previous treatment and molecular characteristics.
Prognosis and Outlook:
The outlook for someone with ALL depends on many factors, including age, leukemia subtype, genetic characteristics, disease burden and—most importantly—how well the leukemia responds to treatment.
Outcomes for children have improved dramatically over several decades. The National Cancer Institute reports that five-year survival for children younger than 15 with ALL has reached approximately 90% in the United States.
Adults generally have less favorable outcomes than children, although treatment continues to evolve and newer targeted and immune-based therapies are expanding the options available to some patients.
Survival statistics describe outcomes across groups of patients and cannot predict what will happen to an individual. A patient's hematologist/oncologist is best positioned to explain their personal prognosis.
Access to Treatment for Acute Lymphoblastic Leukemia:
For some patients with ALL, an appropriate medicine may not be readily available in their country. This can create an additional challenge when treatment needs to be initiated or continued within a clinically appropriate timeframe.
Medicines such as
Blincyto (blinatumomab) may require specialist handling, appropriate documentation and compliance with the regulatory requirements of the destination country.
We facilitate such medicines under the Named Patient Program (NPP) provisions. NPP can provide a structured pathway for facilitating access to certain medicines for eligible patients when the required treatment is unavailable through routine local channels.
We facilitate access to medicines through appropriate sourcing, documentation, regulatory and logistics pathways, subject to the applicable laws and requirements of the destination country.
For healthcare professionals seeking access to Blincyto or other specialist medicines for an eligible patient, our team can help explore the appropriate access pathway
Frequently Asked Questions:
Is acute lymphoblastic leukemia curable?
ALL can be successfully treated, and many patients achieve long-term remission. Outcomes are particularly favorable in children, although prognosis varies according to disease characteristics and response to treatment.
Is ALL more common in children or adults?
ALL can occur at any age, but it is particularly common in children and is the most common childhood cancer. Adults can also develop ALL, although the disease behaves differently across age groups.
What are the main types of ALL?
The two major types are B-cell ALL and T-cell ALL. B-cell ALL is more common.
What is Blincyto used for?
Blincyto (blinatumomab) is an immunotherapy used for certain patients with CD19-positive B-cell precursor ALL. Its use depends on disease status, patient age and other clinical characteristics.
Is Blincyto chemotherapy?
No. Blincyto is an immunotherapy, specifically a bispecific T-cell engager. It works by helping T cells recognize and attack CD19-positive leukemia cells.
Can ALL come back after treatment?
Yes. ALL can relapse after remission. If this happens, treatment options may include immunotherapy, targeted therapy, chemotherapy, CAR T-cell therapy and/or stem cell transplantation depending on the individual case.
Can patients access ALL medicines that are unavailable in their country?
In some circumstances, a Named Patient Program or another appropriate regulatory access pathway may facilitate access to a medicine that is not routinely available locally. Eligibility and requirements vary by country and individual patient circumstances.
Key Takeaways:
- Acute lymphoblastic leukemia (ALL) is a rapidly progressing cancer of the blood and bone marrow.
- It can affect children and adults, although it is particularly common in childhood.
- ALL develops when abnormal immature lymphoid cells multiply and interfere with normal blood-cell production.
- Symptoms can include fatigue, fever, infections, bruising, bleeding, bone pain and swollen lymph nodes.
- Diagnosis generally involves blood and bone marrow testing, with additional immunophenotypic and genetic testing.
- Treatment can include chemotherapy, targeted therapy, immunotherapy, CNS-directed treatment and stem cell transplantation, depending on the individual case.
- Childhood outcomes have improved substantially, with five-year survival approaching 90% for children younger than 15 in U.S. data.
- When a required medicine is unavailable locally, a structured Named Patient Program may help facilitate access where permitted by applicable regulations.
Medical Disclaimer:
This article is intended for general educational purposes and should not replace advice from a qualified healthcare professional. ALL is a serious condition requiring specialist evaluation and individualized treatment. Treatment decisions should always be made by the patient's treating hematologist/oncologist.
Sources and Medical References:
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Huang YH, Wan CL, Dai HP, Xue SL. Targeted and immune-based treatment strategies for T-cell acute lymphoblastic leukemia/lymphoma. Annals of Hematology. 2023;102(8):2001–2013. PubMed:
https://pubmed.ncbi.nlm.nih.gov/37227492/Leukemia & Lymphoma Society. Acute Lymphoblastic Leukemia: disease information, treatment approaches and patient resources. (Leukemia & Lymphoma Society resource)
Moorman AV, Antony G, Wade R, et al. Long-term outcomes from the UKALL2003 study: time to cure in childhood and young-adult acute lymphoblastic leukemia. Journal of Clinical Oncology. 2022;40(36):4228–4239.
PubMed
National Cancer Institute. Cancer in Children and Adolescents: childhood cancer information, diagnosis and treatment overview. Updated August 27, 2024.
National Cancer Institute resource
Sedick Q, Alotaibi S, Alshieban S, Naheet KB, Elyamany G. Natural killer-cell lymphoblastic leukemia/lymphoma: a case report and review of the published literature. Case Reports in Oncology. 2017;10(2):588–595.
https://pmc.ncbi.nlm.nih.gov/articles/PMC5567073/
