Acute Lymphocytic Leukemia

Acute lymphocytic leukemia is a fast-moving cancer of the blood and bone marrow that primarily affects white blood cells called lymphocytes. While it’s the most common cancer in children, adults can develop it too, and treatment approaches offer hope for many patients.

Table of contents

• What is acute lymphocytic leukemia?
• Types of acute lymphocytic leukemia
• Signs and symptoms
• Causes and risk factors
• How the disease is diagnosed
• Treatment approaches
• Outlook and prognosis
• Coping with the diagnosis

What is acute lymphocytic leukemia?

Acute lymphoblastic leukemia, ALL

Acute lymphocytic leukemia is a type of cancer that affects the blood and bone marrow, which is the spongy tissue inside bones where blood cells are made^[1]. The word “acute” means the disease progresses rapidly and creates immature blood cells rather than mature ones. The word “lymphocytic” refers to the white blood cells called lymphocytes, which are a type of white blood cell that normally helps your body fight infection^[1].

• Bone marrow
• Blood
• Lymph nodes
• Spleen
• Liver
• Central nervous system (brain and spinal cord)

In ALL, the bone marrow makes too many lymphocytes that are abnormal and cannot fight infection very well^[3]. These abnormal cells, also called blast cells or leukemia cells, build up in the bone marrow and blood. They crowd out the healthy blood cells, which can lead to infection, anemia (a condition where you don’t have enough red blood cells), and easy bleeding^[3].

Acute lymphocytic leukemia makes up less than 1% of all cancers in the United States^[4]. It is the most common type of cancer in children, particularly affecting those ages 2 to 5, and treatments result in a good chance for a cure^[1]. The disease can also occur in adults, though the chance of a cure is reduced compared to children^[1].

ALL accounts for approximately 2 percent of lymphoid neoplasms in the United States and occurs slightly more frequently in males than females and three times as frequently in Caucasians as in African Americans^[2].

Types of acute lymphocytic leukemia

There are two main types of acute lymphocytic leukemia, based on which type of lymphocyte is affected^[4]:

B-cell acute lymphoblastic leukemia is the most common type. It affects B cells, which are lymphocytes that make antibodies and fight infection. This type accounts for about 85% of childhood cases and 75% to 80% of all adult cases^[4].

T-cell acute lymphoblastic leukemia affects T cells, which are lymphocytes that kill germs and support other immune cells. It makes up around 25% of adult cases and 12% to 15% of childhood cases^[4].

A third type, natural killer ALL, is very rare^[4].

Signs and symptoms

The signs and symptoms of acute lymphocytic leukemia often develop because the disease affects the production of normal blood cells. Patients typically present with symptoms related to anemia, thrombocytopenia (low platelet count), and neutropenia (low white blood cell count) due to the replacement of the bone marrow with the tumor^[2].

Common symptoms include^[1][3][4]:

• Weakness or feeling tired
• Fever or night sweats
• Easy bruising or bleeding, including bleeding from the gums or frequent nosebleeds
• Petechiae, which are tiny red dots under the skin caused by bleeding
• Shortness of breath
• Pale skin
• Frequent infections
• Bone or joint pain
• Loss of appetite
• Unintentional weight loss
• Swollen lymph nodes in the neck, armpits, abdomen, or groin

Additional symptoms can occur if the cancer spreads. Hepatomegaly (enlarged liver), splenomegaly (enlarged spleen), and lymphadenopathy can be seen in up to half of adults on presentation^[2]. Central nervous system involvement is common and can be accompanied by cranial neuropathies or symptoms related to increased intracranial pressure, such as headaches, nausea and vomiting, and seizures^[2].

Many signs and symptoms of acute lymphocytic leukemia mimic those of the flu. However, flu signs and symptoms eventually improve. If signs and symptoms don’t improve as expected, make an appointment with your doctor^[1].

Causes and risk factors

Acute lymphocytic leukemia occurs when a bone marrow cell develops changes, called mutations, in its genetic material or DNA^[1]. The cause of these genetic changes is unknown^[2]. Young children with ALL may have had gene changes that happened before they were born. In adults, the disease may be linked to some carcinogens (cancer-causing substances), including tobacco^[4].

Certain factors can increase the chances of developing acute lymphocytic leukemia^[3][4]:

• Age: The highest risk is in children under 15 and adults over 50
• Sex: Girls under age 1 are at higher risk than boys. After age 1, the risk is higher for males
• Race: People who are white have a slightly higher risk
• Genetic disorders: Conditions like Down syndrome or Fanconi anemia can raise the risk
• Previous chemotherapy or radiation therapy: Having had these treatments increases risk
• Radiation exposure: Risk increases with exposure during fetal development or from high levels of radiation
• Viruses: Infections like Epstein-Barr virus and human T-cell leukemia virus may raise the risk

How the disease is diagnosed

A healthcare provider will start with a physical exam and ask about symptoms. They’ll want to know how long they’ve lasted and how they interfere with everyday life^[4].

To diagnose ALL and determine which subtype you have, your healthcare provider may use several tests^[3][8]:

Blood tests may reveal too many or too few white blood cells, not enough red blood cells, and not enough platelets. A blood test may also show the presence of blast cells, which are immature cells normally found only in the bone marrow^[8]. These include a complete blood count (CBC) with differential, blood chemistry tests, and blood smear^[3].

Bone marrow tests are essential for diagnosis. During bone marrow aspiration and biopsy, a needle is used to remove a sample of bone marrow, usually from the hipbone or breastbone. The sample is sent to a lab for testing to look for leukemia cells^[8]. Doctors in the lab will classify blood cells into specific types based on their size, shape, and other genetic or molecular features. They also look for certain changes in the cancer cells and determine whether the leukemia cells began from B lymphocytes or T lymphocytes^[8].

Genetic tests look for gene and chromosome changes that can help guide treatment decisions^[3].

Imaging tests such as X-rays, computed tomography (CT) scans, positron emission tomography (PET) scans, or magnetic resonance imaging (MRI) may be used to see whether the cancer has spread^[3][4].

Lumbar puncture, also called a spinal tap, is a procedure to collect and test cerebrospinal fluid (CSF) to check if the cancer has spread to the central nervous system^[3].

Treatment approaches

Treatment for acute lymphocytic leukemia usually needs to start quickly after diagnosis^[13]. The main treatment is chemotherapy, which uses medicines to kill cancer cells^[3][13]. Patients usually receive a combination of chemotherapy medicines.

Treatment is typically divided into different phases^[9][11]:

Induction involves getting several strong chemotherapy drugs. The goal of induction is to kill most or all of the cancer cells, achieving what is called remission. During this phase, doctors may also give treatments to kill any cancer cells in the brain, such as chemotherapy drugs in the spinal fluid or radiation therapy to the brain^[5].

Consolidation involves getting different chemotherapy drugs for a few months to keep the leukemia from coming back. Doctors may also give stem cell treatment if needed^[5].

Maintenance involves getting chemotherapy for 2 to 3 years, sometimes in low amounts^[5].

Additional treatments may include^[3][13]:

• Steroids: Steroid medicine aims to get rid of the leukemia cells and is usually taken for up to a week before starting chemotherapy
• Targeted therapy: Uses drugs or other substances that attack specific cancer cells with less harm to normal cells
• Immunotherapy: Uses medicines to help the immune system kill cancer cells, such as CAR T-cell therapy
• Radiation therapy: Uses high-energy rays to kill cancer cells
• Stem cell transplant: Replaces damaged blood cells with healthy ones and may be used if the cancer has come back or is likely to come back

Supportive treatments are also offered to prevent or control symptoms. This may include medicines such as antibiotics to prevent or treat infections, blood transfusions, medicines called growth factors to help the bone marrow make blood cells, and vaccines to help protect from illnesses such as flu and COVID-19^[13].

Chemotherapy may make patients sicker before they get better. The medicines may make them more likely to get infections, require blood transfusions, or cause side effects such as vomiting, weakness, tiredness, or hair loss^[5].

Outlook and prognosis

Acute lymphocytic leukemia is a serious condition, but treatment can help. In many cases, it can cure the disease^[4]. About 8 in 10 children and 4 in 10 adults with ALL are cured, meaning they survive at least 5 years^[5].

The goal of treatment is to reach a complete remission, which means that the numbers of blood cells have returned to normal levels and less than 5% of cells in the bone marrow are immature white blood cells. With complete remission, there are no general signs or symptoms of ALL and no signs that the disease has spread to the central nervous system or anywhere else in the body^[16].

Doctors consider ALL cured if it doesn’t relapse (come back) within 5 years^[5]. If ALL comes back after treatment, doctors may do additional chemotherapy or radiation therapy^[5].

Sometimes acute lymphocytic leukemia might be very hard to treat, and it may not be possible to cure the cancer. If this is the case, the aim of treatment will be to limit the cancer and its symptoms, and help patients live longer^[13]. Patients will be referred to a special team of doctors and nurses called the palliative care team or symptom control team, who will work to help manage symptoms and make patients more comfortable^[13].

Coping with the diagnosis

Coping with a diagnosis of acute lymphocytic leukemia can be overwhelming. Patients may experience a range of powerful emotions such as feeling shocked, upset, numb, frightened and uncertain, confused, angry, or sad^[17]. Everyone reacts in their own way, and patients need to do what’s right for them to help them cope.

Getting information about the type of cancer and its treatment can help patients be more able to cope and make decisions. However, taking in information can be difficult, especially when just diagnosed. Patients should make a list of questions before seeing their doctor and take someone with them to help remember what they want to ask^[17].

Talking to friends and relatives about cancer can help and support patients, though some people may be scared of the emotions this could bring up. Patients should help their family and friends by letting them know if they would like to talk about what’s happening and how they feel^[17]. Patients might also find it easier to talk to someone other than their own friends and family, such as a counselor.

Patients will have a clinical nurse specialist (CNS) who will support them throughout their treatment. The specialist nurse is the main contact and can be called if patients have questions or worries. They can help with any information patients don’t understand, provide emotional and psychological support, recommend support services such as a psychiatrist, social worker or counselor, and help patients contact them^[17].

Patients should remember that they don’t have to sort everything out at once. It might take some time to deal with each issue, and it’s okay to ask for help if needed. Practical things like making lists, having a calendar with all appointments, having goals, and planning enjoyable things can also help^[17].