Childhood leukemia and its treatment

Leukemia is the most common cancer in children and teens, accounting for almost 1 out of 3 cancers. Most childhood leukemias are acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML), with chronic leukemias being rare in children. In AML, myeloid stem cells abnormally develop into immature white blood cells called myeloblasts that do not mature into healthy cells, accumulating in the blood and bone marrow and making it difficult for healthy white blood cells, red blood cells, and platelets to thrive — leading to infection, anemia, and bleeding. Leukemia cells can also travel beyond the blood to the central nervous system, skin, and gums, and can sometimes form a solid tumor called a myeloid sarcoma. In ALL, too many stem cells turn into abnormal lymphoblasts that cannot fight infection effectively, similarly crowding out healthy blood cells and platelets.

Chemotherapy for most children with AML is divided into two phases: induction and consolidation. Because of the intensity of treatment and the potential for serious complications, children with AML should be treated at cancer centers or hospitals with experience in this disease. During induction, the most commonly used chemotherapy medicines are daunorubicin and cytarabine, administered for several consecutive days and repeated in 10-day or 2-week intervals depending on desired treatment intensity. Some children may also receive gemtuzumab ozogamicin (Mylotarg) as a targeted addition to chemotherapy, and agents like etoposide or 6-thioguanine may be added for high-risk cases. Most children also receive intrathecal chemotherapy — delivered directly into the cerebrospinal fluid — to prevent leukemia from relapsing in the brain or spinal cord. Between 85% and 90% of children with AML enter remission after induction therapy, though this does not necessarily mean the leukemia has been cured.

The consolidation phase follows induction with the goal of eliminating any remaining leukemia cells using more aggressive treatment, primarily heavy doses of cytarabine. For children with a suitable sibling stem cell donor, a stem cell transplant may be recommended — particularly when AML has unfavorable prognostic markers — as studies have shown this improves long-term survival over chemotherapy alone, though with increased risk of serious complications. For children without a suitable donor, aggressive chemotherapy remains the standard consolidation approach. Supportive care — including nursing care, nutritional support, antibiotics, and blood transfusions — is a critical element of AML treatment, as aggressive therapy often destroys much of the bone marrow and causes significant blood cell shortages.

Children with ALL have access to several treatment options, including chemotherapy, radiation therapy, stem cell transplant, targeted therapy, and CAR T-cell therapy. Chemotherapy may be administered systemically through the bloodstream or as intrathecal chemotherapy directly into the cerebrospinal fluid to target cancer cells in the brain and spinal cord, and is often given as combination chemotherapy using multiple anticancer drugs — with higher doses for high-risk ALL than for standard-risk cases. Radiation therapy may be used for ALL that has spread to the brain, spinal cord, or testicles, or to prepare bone marrow for a stem cell transplant. Stem cell transplantation is rarely used as a first-line treatment for childhood ALL but is increasingly being used as part of relapse treatment.

Targeted therapy offers more precise treatment with less harm to normal cells compared to chemotherapy. Tyrosine kinase inhibitors (TKIs) such as imatinib mesylate and dasatinib are used in the treatment of Philadelphia chromosome-positive ALL, while ruxolitinib is being studied for newly diagnosed high-risk ALL. Monoclonal antibodies such as blinatumomab and inotuzumab are being studied for refractory childhood ALL and standard-risk ALL, working by attaching to specific targets on cancer cells and blocking their growth or killing them directly.

CAR T-cell therapy represents a new and groundbreaking approach to treating acute lymphoblastic leukemia in children. In this treatment, T cells are taken from the patient's blood and genetically modified to produce chimeric antigen receptors (CARs) — specialized proteins that help the T cells find and attack cancer cells bearing specific surface markers. When these engineered T cells are reinfused into the patient's body, they multiply and attack cancer cells with high precision, often resulting in remission. While CAR T-cell therapy has demonstrated remarkable potential, it can be associated with serious complications such as cytokine release syndrome and neurotoxicity, underscoring the continued need for research and refinement to make it safer and more broadly accessible for pediatric patients.