- What is childhood acute lymphoblastic leukemia (ALL)?
- What are causes and risk factors for childhood acute lymphoblastic leukemia (ALL)?
- What are symptoms and signs of childhood acute lymphoblastic leukemia (ALL)?
- How is childhood acute lymphoblastic leukemia (ALL) diagnosed?
- What is the prognosis for childhood acute lymphoblastic leukemia (ALL)?
- What are the stages of childhood acute lymphoblastic leukemia (ALL)?
- What is recurrent childhood acute lymphoblastic leukemia (ALL)?
- What is the treatment for childhood acute lymphoblastic leukemia (ALL)?
- What treatments are being tested in clinical trials?
- What is the treatment for recurrent childhood acute lymphoblastic leukemia (ALL)?
In childhood ALL, risk groups are used instead of stages.
Because ALL is a disease of the blood cells, it has already spread throughout the body at diagnosis. There is no staging system for ALL. Risk groups are used to plan treatment.
Risk groups are described as:
- Standard (low) risk: Includes children aged 1 to 9 years who have a white blood cell count of less than 50,000/µL at diagnosis.
- High risk: Includes children younger than 1 year or older than 9 years and children who have a white blood cell count of 50,000/µL or more at diagnosis.
Other factors that affect the risk group include the following:
- Whether the leukemia cells formed from B lymphocytes or T lymphocytes.
- Whether there are certain changes in the chromosomes of the lymphocytes.
- How quickly the leukemia responds to initial therapy.
It is important to know the risk group in order to plan treatment. Children with high risk ALL usually receive more aggressive treatment than children with standard risk ALL.
What is recurrent childhood acute lymphoblastic leukemia (ALL)?
Recurrent childhood ALL is cancer that has recurred (come back) after it has been treated. The leukemia may come back in the blood and bone marrow, brain, testicles, spinal cord, or in other parts of the body.
There are different types of treatment for childhood acute lymphoblastic leukemia (ALL).
Different types of treatment are available for children with acute lymphoblastic leukemia (ALL). Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment.
Because cancer in children is rare, taking part in a clinical trial should be considered. Some clinical trials are open only to patients who have not started treatment.
Children with ALL should have their treatment planned by a team of doctors with expertise in treating childhood leukemia.
Treatment will be overseen by a pediatric oncologist, a doctor who specializes in treating children with cancer. The pediatric oncologist works with other pediatric health professionals who are experts in treating children with leukemia and who specialize in certain areas of medicine. These may include the following specialists:
- Medical oncologist.
- Pediatric surgeon.
- Radiation oncologist.
- Pediatric nurse specialist.
- Social worker.
- Rehabilitation specialist.
Regular follow-up exams are very important. Side effects can result from treatment long after it ends. These are called late effects. Radiation therapy to the head may affect the child's developing brain and cause changes in mood, feelings, thinking, learning, or memory. Late effects of treatment for ALL also include the risk of second cancers (new types of cancer), especially brain tumors. Early diagnosis and treatment of these secondary brain tumors may help lower the risk from these brain tumors. Children younger than 4 years have a higher risk of side effects from radiation therapy to the brain. It is important to talk with your child's doctors about the possible late effects caused by some treatments.
The treatment of childhood ALL usually has 3 phases.
The treatment of childhood ALL is done in phases:
- Induction therapy: This is the first phase of treatment. Its purpose is to kill the leukemia cells in the blood and bone marrow. This puts the leukemia into remission. This is also called the remission induction phase.
- Consolidation /intensification therapy: This is the second phase of therapy. It begins once the leukemia is in remission. The purpose of consolidation/intensification therapy is to kill any remaining leukemia cells that may not be active but could begin to regrow and cause a relapse.
- Maintenance therapy: This is the third phase of treatment. Its purpose is to kill any remaining leukemia cells that may regrow and cause a relapse. Often the cancer treatments are given in lower doses than those used for induction and consolidation/intensification therapy. This is also called the continuation therapy phase.
Bone marrow biopsy and aspirates are done throughout all phases to see how well the leukemia is responding to treatment.
Treatment called central nervous system (CNS) sanctuary therapy is usually given during induction therapy and consolidation/intensification therapy and is often given during maintenance therapy. Because most anticancer drugs given by mouth or injected into a vein to kill leukemia cells may not reach leukemia cells in the CNS (brain and spinal cord), the leukemia cells are able to find “sanctuary” (hide) in the CNS. Certain anticancer drugs, intrathecal chemotherapy, and radiation therapy to the brain are able to reach leukemia cells in the CNS and are given to kill the leukemia cells and prevent the cancer from recurring (coming back). CNS sanctuary therapy is also called CNS prophylaxis because it is given to stop leukemia cells from growing in the CNS.
Four types of standard treatment are used:
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid (intrathecal), an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). Combination chemotherapy is treatment using more than one anticancer drug. The way the chemotherapy is given depends on the type of the cancer being treated.
Intrathecal chemotherapy or high doses of chemotherapy injected into a vein may be used to treat childhood ALL that has spread, or may spread, to the brain and spinal cord. When used to prevent cancer from spreading to the brain and spinal cord, it is called central nervous system (CNS) sanctuary therapy or CNS prophylaxis. CNS sanctuary therapy is given in addition to chemotherapy by mouth or vein that is intended to kill leukemia cells in the rest of the body. All children with ALL receive CNS sanctuary therapy as part of their treatment.
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. External radiation therapy may be used to treat childhood ALL that has spread, or may spread, to the brain and spinal cord. When used this way, it is called central nervous system (CNS) sanctuary therapy or CNS prophylaxis.
Because radiation therapy to the brain can affect growth and brain development in young children, many children with ALL are treated without radiation therapy. Radiation therapy to the brain and spinal cord is sometimes used as CNS sanctuary therapy to treat children and teenagers in the high risk group. Clinical trials are studying new ways of using radiation therapy that may have fewer side effects, including giving lower doses of radiation.
Chemotherapy with stem cell transplant
Stem cell transplant is a method of giving very high doses of chemotherapy and sometimes radiation therapy, and then replacing the blood-forming cells destroyed by the cancer treatment. Stem cells (immature blood cells) are removed from the blood or bone marrow of a donor. After the patient receives very high doses of chemotherapy and sometimes radiation therapy, the donor's stem cells are given back to the patient through an infusion. These reinfused stem cells grow into (and restore) the patient's blood cells. A stem cell transplant may use stem cells from a donor who is or is not related to the patient.
Stem cell transplant is rarely used as initial treatment for children and teenagers with ALL. It is used more often as part of treatment for ALL that relapses (comes back after treatment).
|Stem cell transplant (Step 1). Blood is taken from a vein in the arm of the donor. The patient or another person may be the donor. The blood flows through a machine that removes the stem cells. Then the blood is returned to the donor through a vein in the other arm.|
|Stem cell transplant (Step 2). The patient receives chemotherapy to kill blood-forming cells. The patient may receive radiation therapy (not shown).|
|Stem cell transplant (Step 3). The patient receives stem cells through a catheter placed into a blood vessel in the chest.|
Targeted therapy is a treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells.
Tyrosine kinase inhibitors (TKIs) are targeted therapy drugs that block the enzyme, tyrosine kinase, which causes stem cells to develop into more white blood cells (granulocytes or blasts) than the body needs. For example, imatinib mesylate (Gleevec) is a TKI used in the treatment of children with Philadelphia chromosome -positive ALL.