Childhood Leukemia

What is childhood leukemia?

Childhood leukemia is a cancer of the blood and bone marrow that occurs in infants, children, and teenagers. The bone marrow is the soft, spongy tissue inside bones where blood cells are made. In leukemia, the bone marrow begins to produce large numbers of abnormal white blood cells. These abnormal cells do not work properly, and they crowd out the healthy cells the body needs, including red blood cells (which carry oxygen), platelets (which help blood clot), and normal white blood cells (which fight infection).

When people ask what is childhood leukemia, it helps to know that leukemia is not a single disease. There are several types, and they behave differently. The most common type in children is acute lymphoblastic leukemia (often shortened to ALL), which affects immature lymphocytes, a kind of white blood cell. The second most common type is acute myeloid leukemia (AML), which affects a different group of blood-forming cells. You can read more about that type on the page about acute myelogenous leukemia. Chronic leukemias, which develop more slowly, are much less common in children than in adults.

Leukemia is the most common cancer diagnosed in children, although childhood cancer overall remains rare. It can occur at any age, from infancy through the teenage years. Acute lymphoblastic leukemia is diagnosed most often in young children, while acute myeloid leukemia can appear at any age in childhood. Because acute leukemias develop quickly, symptoms often appear over days to weeks rather than months, and prompt evaluation matters.

Symptoms of childhood leukemia

Childhood leukemia symptoms happen mainly because abnormal cells crowd out healthy blood cells in the bone marrow. When there are too few red blood cells, a child may look pale and feel tired. When there are too few platelets, a child may bruise or bleed easily. When normal white blood cells are reduced, infections may occur more often or last longer than expected.

Common childhood leukemia symptoms include:

• Persistent tiredness or weakness — often with pale skin, caused by anemia (a shortage of red blood cells)
• Frequent or lingering infections — including fevers that keep returning without a clear cause
• Easy bruising or bleeding — such as frequent nosebleeds, bleeding gums, or small red or purple spots on the skin (called petechiae)
• Bone or joint pain — leukemia cells can build up inside bones; young children may limp or refuse to walk
• Swollen lymph nodes — painless lumps in the neck, armpit, or groin
• A swollen belly — caused by an enlarged liver or spleen
• Loss of appetite and weight loss
• Night sweats

Symptoms can differ somewhat by type. In acute leukemias (ALL and AML), symptoms usually develop quickly and may become severe within weeks. If leukemia cells spread to the brain and spinal cord, a child may have headaches, vomiting, blurred vision, or trouble with balance. In some cases of AML, leukemia cells collect under the skin or in the gums, causing lumps or gum swelling. A type of ALL that involves T cells can sometimes cause a mass in the chest, leading to coughing or trouble breathing. Chronic leukemias, which are rare in children, may cause milder symptoms that develop slowly, and are sometimes found on a routine blood test before symptoms appear.

It is important to remember that all of these symptoms are much more often caused by common childhood illnesses than by leukemia. However, when several of these signs appear together, or when they persist and do not improve, a medical evaluation is needed.

Causes and risk factors

In most cases, doctors cannot identify a specific cause for an individual child’s leukemia. What is known is that leukemia begins when the DNA (the genetic material) inside developing blood cells changes in a way that makes the cells grow uncontrollably and fail to mature. These genetic changes usually happen during the child’s lifetime, often by chance, rather than being inherited from a parent.

When discussing childhood leukemia causes, researchers distinguish between the biological changes inside the cells and the risk factors that make those changes somewhat more likely. Recognized risk factors include:

• Certain genetic conditions — children with Down syndrome have a higher risk of both ALL and AML; some other rare inherited syndromes, such as Li-Fraumeni syndrome and certain bone marrow failure disorders, also raise the risk
• Previous cancer treatment — earlier chemotherapy or radiation therapy for another cancer can, in a small number of children, increase the risk of a later leukemia
• High doses of radiation — exposure to significant ionizing radiation is a known risk factor; routine medical imaging uses far lower doses
• A sibling with leukemia — the risk is slightly higher in a child whose brother or sister had leukemia, and higher again in identical twins, though most siblings never develop the disease
• Weakened immune system — some inherited immune conditions or long-term medicines that suppress the immune system may raise risk

Everyday factors that parents often worry about — such as living near power lines, ordinary household chemicals, or vaccines — have not been shown to cause childhood leukemia. Importantly, nothing a parent did or did not do is known to cause a child’s leukemia, and the disease is not contagious. Most children who develop leukemia have no identifiable risk factor at all.

Diagnosis

Childhood leukemia diagnosis begins with a careful medical history and physical examination. The doctor will ask about symptoms, check for pale skin, bruising, swollen lymph nodes, and an enlarged liver or spleen, and then order tests. Because the symptoms overlap with many common illnesses, blood tests are the essential first step.

Blood tests. A complete blood count (CBC) measures the numbers of red blood cells, white blood cells, and platelets. In leukemia, results are often abnormal — for example, low red cells and platelets, and white cell counts that may be very high or very low. A blood smear, in which a drop of blood is examined under a microscope, may show immature leukemia cells, called blasts.

Bone marrow aspiration and biopsy. This is the key test that confirms the diagnosis. Using a thin needle, usually inserted into the back of the hip bone while the child is sedated or under anesthesia, doctors remove a small sample of liquid marrow (aspiration) and sometimes a tiny core of bone and marrow (biopsy). A diagnosis of acute leukemia is generally confirmed when a significant proportion of the cells in the marrow are blasts, together with the results of specialized testing.

Specialized laboratory tests. The marrow and blood samples undergo further analysis to identify the exact type and subtype of leukemia. Flow cytometry (a test that identifies markers on the surface of cells) distinguishes ALL from AML and identifies subtypes. Genetic and chromosome tests (cytogenetics and molecular testing) look for specific changes in the leukemia cells’ DNA. These results guide treatment choices and help predict how the leukemia is likely to respond.

Lumbar puncture (spinal tap). A small sample of the fluid surrounding the brain and spinal cord (cerebrospinal fluid) is collected through a thin needle in the lower back, usually under sedation. This shows whether leukemia cells have reached the central nervous system, which affects the treatment plan.

Imaging. A chest X-ray may be done to look for a mass in the chest or signs of infection. Ultrasound can assess the liver, spleen, and kidneys. Imaging is used to evaluate specific problems rather than to diagnose leukemia itself. Advanced imaging such as PET-CT imaging is used more often in lymphomas than in leukemia, but doctors may order it in selected situations, for example when disease outside the marrow is suspected.

Unlike many solid cancers, leukemia is not described using numbered stages, because it involves the blood and marrow from the start. Instead, doctors classify it by type, subtype, genetic features, and risk group, and they check whether it involves the central nervous system.

Treatment options

Childhood leukemia treatment depends on the type and subtype of leukemia, the child’s age, the results of genetic testing, and how the disease responds to the first phase of therapy. Care is coordinated by pediatric hematologist-oncologists — specialists in children’s blood disorders and cancers — working within a pediatric oncology team that also includes nurses, pharmacists, psychologists, and other supportive specialists. In many hospitals, including Acibadem, this care is organized through dedicated oncology services such as the medical oncology department working alongside pediatric teams.

Chemotherapy. Chemotherapy — medicines that destroy fast-growing cells — is the main treatment for acute childhood leukemia. It is usually given in phases:

• Induction: intensive treatment over the first weeks, aiming to bring the leukemia into remission, meaning no leukemia cells can be detected by standard tests
• Consolidation (intensification): further treatment to destroy any remaining leukemia cells
• Maintenance: in ALL, lower-dose treatment continued for an extended period, often around two years or more, to reduce the chance of the leukemia returning

Because leukemia can hide in the brain and spinal cord, chemotherapy is also given directly into the spinal fluid (called intrathecal chemotherapy) during lumbar punctures. Overall approaches to leukemia and lymphoma treatment follow internationally recognized protocols that have been refined over decades of clinical trials.

Targeted therapy. Some leukemias carry specific genetic changes that can be attacked with targeted medicines. For example, leukemias with the Philadelphia chromosome (a particular genetic change) can be treated with drugs called tyrosine kinase inhibitors alongside chemotherapy. Testing the leukemia cells at diagnosis identifies children who may benefit.

Immunotherapy. Newer treatments help the immune system recognize and destroy leukemia cells. One approach is CAR-T cell therapy, in which some of the child’s own immune cells (T cells) are collected, modified in a laboratory to recognize leukemia cells, and returned to the body. It is currently used mainly for certain children with ALL that has come back or has not responded to standard treatment. Other immunotherapy medicines, such as antibody-based drugs, may also be used in specific situations.

Stem cell (bone marrow) transplant. For some children — particularly those with high-risk AML, or leukemia that returns after treatment — doctors may recommend a stem cell transplant. This involves high-dose chemotherapy, sometimes with radiation, followed by an infusion of healthy blood-forming stem cells from a donor. It is an intensive procedure reserved for situations where it offers a clear advantage.

Radiation therapy. Radiation is used less often than in the past, but it may be recommended in selected cases, such as leukemia involving the central nervous system or as part of preparation for a transplant.

Supportive care. Treatment also includes transfusions of red blood cells and platelets, antibiotics and other medicines to prevent and treat infection, nutrition support, and medicines to control nausea and pain. Supportive care is a central part of childhood leukemia treatment, not an afterthought.

What about surgery and watchful waiting? Surgery is not used to treat leukemia itself, because the disease is spread through the blood and marrow rather than forming a single tumor that can be removed. Minor procedures are common, however — most children have a central line or port (a small device placed under the skin) inserted so that medicines can be given and blood drawn without repeated needle sticks. Watchful waiting is not appropriate for acute childhood leukemias, which require prompt treatment; it may occasionally be considered in certain rare, slow-growing childhood blood disorders, but only under close specialist supervision.

Living with childhood leukemia and outlook

A leukemia diagnosis changes daily life for the whole family. Treatment often involves hospital stays, frequent clinic visits, and periods when the child must avoid crowds and sick contacts because of a weakened immune system. Schooling may need to be adjusted, and siblings and parents often need support too. Child life specialists, psychologists, and social workers can help families cope, and many families find that connecting with support groups for childhood cancer is valuable.

The outlook for childhood leukemia has improved dramatically over recent decades. With modern treatment, a large majority of children with acute lymphoblastic leukemia achieve long-term remission, and outcomes for acute myeloid leukemia have also improved, although AML generally remains harder to treat than ALL. That said, outcomes vary widely depending on the leukemia’s type, genetic features, the child’s age, and how well the disease responds to early treatment. No doctor can promise a particular outcome for an individual child, and your care team is the best source of information about your child’s specific situation.

After treatment ends, children continue regular follow-up visits for years. These visits check for any sign of the leukemia returning and monitor for late effects of treatment, which can include effects on growth, heart function, hormones, learning, and fertility. Long-term survivorship care helps identify and manage these issues early. Most survivors of childhood leukemia go on to attend school, work, and live full adult lives, though ongoing health monitoring is generally recommended.

Frequently asked questions

What is childhood leukemia in simple terms?

Childhood leukemia is a cancer of the blood-forming cells in the bone marrow. The marrow starts making large numbers of abnormal white blood cells that do not work properly and crowd out healthy blood cells. This leads to symptoms such as tiredness, pale skin, easy bruising, and frequent infections. The most common types in children are acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML).

Can childhood leukemia be cured?

In many cases, yes. With current treatment protocols, most children with acute lymphoblastic leukemia achieve lasting remission, and many are considered cured after years without disease. Outcomes for acute myeloid leukemia have also improved, though it is generally more challenging to treat. However, results vary from child to child depending on the leukemia’s features and its response to treatment, so no outcome can be guaranteed. Your child’s care team can explain what the findings mean in your specific case.

What are the first signs of leukemia in a child?

Early childhood leukemia symptoms are often vague and can look like common illnesses. Typical first signs include unusual tiredness, pale skin, fevers that keep returning, easy bruising or unexplained bleeding, bone or leg pain (sometimes causing a limp), and swollen lymph nodes. Because these signs have many possible causes, a doctor’s evaluation with a blood test is the appropriate next step when they persist or occur together.

How serious is childhood leukemia?

Acute childhood leukemia is a serious illness that requires prompt specialist treatment — untreated acute leukemia progresses quickly. At the same time, it is one of the childhood cancers with the most established and effective treatments, and long-term survival has improved greatly over the decades. Seriousness at diagnosis depends on the type, the child’s condition, and complications such as infection or bleeding, which is why urgent evaluation matters when leukemia is suspected.

How long does childhood leukemia treatment take?

It depends on the type. Treatment for acute lymphoblastic leukemia typically lasts around two years or more, with intensive phases at the beginning followed by a longer, gentler maintenance phase, much of which can be given as an outpatient. Treatment for acute myeloid leukemia is usually shorter but more intensive, often involving several cycles of hospital-based chemotherapy over a number of months. Children who need a stem cell transplant have a different timeline. Your care team can outline the plan expected for your child’s specific diagnosis.

Is childhood leukemia hereditary or caused by something parents did?

In the great majority of cases, no. The genetic changes that cause leukemia usually arise by chance in the child’s own developing blood cells and are not inherited. A small number of children have genetic conditions, such as Down syndrome, that raise the risk. There is no evidence that anything parents did during pregnancy or afterward — including diet, ordinary household exposures, or vaccination — causes childhood leukemia.

Can childhood leukemia come back after treatment?

Yes, a relapse (return of the leukemia) is possible, which is why children are followed closely for years after treatment ends. If leukemia does come back, further treatment options often exist, including different chemotherapy combinations, immunotherapy such as CAR-T cell therapy for eligible children with ALL, and stem cell transplant. The chance of relapse and the options available depend on the leukemia’s type and features, and the care team will discuss these openly with the family.

When to see a doctor

Contact your child’s doctor promptly if your child has persistent tiredness, unexplained pale skin, fevers that keep returning, unexplained bruising, swollen lymph nodes that do not go away, ongoing bone or joint pain, or unexplained weight loss — especially if several of these occur together or last more than a couple of weeks.

Seek urgent or emergency medical care if your child has any of the following red-flag signs:

• High fever in a child known or suspected to have low white blood cells, or fever with shaking chills and a child who seems very unwell
• Bleeding that will not stop, such as a prolonged nosebleed, blood in the urine or stool, or widespread small red or purple spots appearing on the skin
• Severe headache with vomiting, blurred vision, confusion, or a seizure
• Difficulty breathing, chest pain, or swelling of the face and neck
• Extreme paleness with severe weakness, dizziness, or fainting
• A child who suddenly cannot walk or bear weight because of pain or weakness

These signs do not always mean leukemia, but they always deserve immediate medical attention. Early evaluation allows doctors to find the cause quickly and, if leukemia is diagnosed, to begin treatment without delay — which is when treatment works best.