What is leukemia? Features of the course in a child
Leukemia is a cancer that starts in the blood-forming cells found in the bone marrow. Most often, leukemia in children affects leukocytes, but some leukemias begin with other types of blood cells.
Any blood-producing cell in the bone marrow can turn into a leukemic cell. Once this change occurs, the abnormal cells no longer fully mature. They can multiply quickly and not die when needed. These cells grow in the bone marrow and begin to crowd out healthy cells. Affected cells quickly enter the bloodstream. From there, they can travel to other parts of the body: lymph nodes, spleen, liver, central nervous system (brain and spinal cord), testes or other organs, where they will inhibit the work of other cells.
Why does leukemia develop in a child?
The exact cause of most leukemia is unknown.
Genetics
Scientists have found that some changes in DNA inside healthy bone marrow cells can cause them to convert into leukemia cells. Normal human cells grow and function based on information in each cell's DNA. The DNA inside cells makes up genes, which are instructions for how cells are supposed to function.
Children usually look like their parents because they are the DNA source for their child. But human genes also control cell growth, division, and timely death. Certain genes that help cells grow, divide, or stay alive are called oncogenes. Others that inhibit cell division or cause them to die in a timely manner are called tumor suppressor genes (inhibit tumor growth).
DNA mutations or other types of changes that activate oncogenes and turn off suppressor genes can cause cancer. These changes are sometimes inherited from the parent (as can be the case with childhood leukemia), or they occur randomly during a person's life if there is a violation of cell division.
Chromosome translocation - A common type of DNA change that can lead to leukemia. Human DNA is packaged in 23 pairs of chromosomes. During translocation, DNA is detached from one chromosome and attached to another. The point on the chromosome where the break occurs can influence oncogenes or tumor suppressor genes. Other chromosomal changes or transformations in some genes have been found in patients with leukemia.
Risk factors
Genetic
Hereditary syndromes
Some children inherit DNA mutations from their parent, which increases their chances of developing cancer. For example, Li-Fraumeni syndrome, which is the result of an inherited mutation in the tumor suppressor gene TP53, increases the risk of developing the disease, as well as some other types of oncological pathologies.
Children with Down syndrome have an extra (third) copy of chromosome 21. They are many times more likely to develop acute leukemia. Down syndrome has also been associated with transient myeloproliferative disorder (transient myeloproliferative disorder), a leukemic condition in the first month of life that often goes away on its own without treatment.
Some inherited diseases can increase the risk of leukemia, but children usually do not develop leukemia due to inherited mutations. The DNA mutations associated with this cancer occur after conception and are not inherited.
Having a brother or sister with leukemia
If a child has a brother or sister with leukemia, then he has a slightly increased (2-4 times) chance of developing this type of cancer, but the overall risk is still low. The risk is much higher in identical twins. If one of the twins develops leukemia, the other twin is more likely to develop leukemia. This risk is much higher if cancer develops in the first year of life.
Having adult leukemia in a parent does not increase the child's risk of developing the disease.
Exogenous factors
Lifestyle
Lifestyle risk factors for some adults with cancer include: smoking, being overweight, drinking alcohol, and excessive sun exposure. These factors are important for many adult cancers, but are unlikely to be relevant in most childhood cancers.
Some studies have said that if a pregnant woman drank alcohol, the child's risk of developing leukemia was increased, but not all studies found such an association.
Environmental factors
Radiation
Japanese people affected by the atomic attack had a significantly increased risk of developing leukemia, usually 6-8 years after exposure. If in the first months of development the fetus is exposed to radiation, then there is a high probability of developing cancer, but the degree of risk is not clear.
The potential risks of exposing a fetus or baby to lower levels of radiation, such as from x-rays or computed tomography, are unknown.
Some studies have found a slight increase in risk, while others have not shown an increase in the likelihood of developing the disease. There may be a small increase in risk, but to be safe, most doctors recommend that pregnant women and children not undergo these tests unless urgently needed.
Chemotherapy and exposure to other chemicals
Children and adults who are treated for other types of cancer with certain chemotherapy drugs are at greater risk of developing leukemia later in life. Preparations: cyclophosphamide, chlorambucil, etoposide and teniposie - were associated with an increased likelihood of leukemia. It usually develops within 5-10 years after therapy and is difficult to treat.
Exposure to chemicals such as benzene (a solvent used in the cleaning industry and in the manufacture of some drugs, plastics, and dyes) can cause acute leukemia in adults and, rarely, children.
Several studies have found a possible link between childhood leukemia and pesticide exposure, both during fetal development and early childhood. However, most of these studies had serious limitations. More research is needed to try to confirm these findings and provide more specific information about the potential risks.
Several studies have shown that some childhood leukemias can be caused by a combination of genetic and environmental factors. For example, certain genes usually control how the body breaks down and gets rid of harmful chemicals.
Some people have different variations of these genes, making them less effective. Children who inherit these genes may be unable to break down harmful chemicals if they enter the body. The combination of genetics and external influences can increase the risk of developing leukemia.
Classification of leukemia
To understand the different types of leukemia, it is necessary to have an understanding of the composition of the blood and the lymphatic system.
Bone marrow, blood and lymphoid tissue of a healthy person
Bone marrow
Bone marrow is the inner cancellous part of the bone. New blood cells are produced there. In infants, almost all bones have active bone marrow, but during adolescence it remains in the flat bones (skull, shoulder blades, ribs, sternum and thigh bones) and vertebrae.
Bone marrow contains fewer stem cells, more mature blood-forming cells, fat cells, and supporting tissues that help cells grow. Stem cells go through a series of changes to make new blood cells.
Blood cell types
Red cells (erythrocytes) transport oxygen from the lungs to all other tissues in the body and return carbon dioxide back to the lungs, which expel it (exhale). Too few red blood cells (anemia) lead to feeling tired, weak, short of breath, because there is not enough oxygen in the tissues of the body.
Platelets are fragments of cells produced by megakaryocytes (a type of cell in the bone marrow). Platelets play an important role in stopping bleeding by blocking openings in blood vessels. When there are too few platelets (thrombocytopenia), the bleeding that occurs can be difficult to stop.
Leukocytes help the body eliminate infections. With a low level of these cells, immunity weakens, and a person is at a high risk of developing infectious diseases.
Types of leukocytes
Lymphocytes are mature, infection-killing cells that develop from lymphoblasts, a type of stem cell found in the bone marrow. Lymphocytes are the main cells that make up lymphoid tissue (the main part of the defense system). Lymphoid tissue is found in the lymph nodes, thymus (a small organ behind the breastbone), spleen, tonsils and adenoids, and bone marrow. It is also present in the digestive and respiratory systems.
There are 2 main types of lymphocytes:
- B-lymphocytes (B-cells) help protect the body from bacteria and viruses. They produce proteins (antibodies) that attach to the pathogenic organism, marking it for destruction by other components of the defense system;
- T lymphocytes (T cells) also help protect the body from germs. Some types of T cells directly destroy harmful microorganisms, while others increase or slow down the activity of other immune cells.
Granulocytes are advanced, infection-fighting cells that are produced by myeloblasts (a type of blood-forming cell in the bone marrow). Granulocytes have granules containing enzymes and other elements that can kill bacteria.
Monocytes develop from blood-forming monoblasts in the bone marrow and are associated with granulocytes. After circulating in the bloodstream for about one day, monocytes invade body tissues, becoming macrophages, which can destroy some microbes by surrounding and breaking them down. Macrophages also help lymphocytes recognize germs and begin to create antibodies to fight them.
Types of leukemia in children
There are acute (rapidly progressive) leukemia and chronic (slowly progressive). Children almost always develop an acute form.
Acute leukemia in children
Acute lymphoblastic leukemia (ALL)
It is a rapidly developing cancer of the lymphoblasts (cells that form lymphocytes).
ALL is divided into subgroups taking into account the following facts:
- the type of lymphocytes (B or T) from which the cancer cells come out;
- how mature these leukemic cells are.
Allocate:
- B-cell ALL. Occurs in about 80% -85% of children with ALL; leukemia begins in B cells;
- T-cell ALL. Affects about 15% - 20% of children with ALL. This type of leukemia affects boys more than girls and generally affects older children more than B-cell ALL. It often causes the thymus (a small lymphoid organ in front of the trachea) to enlarge, which can sometimes cause breathing problems. This type of leukemia can also spread to the cerebrospinal fluid (CSF) early in the disease.
Acute myeloid leukemia (AML)
It is a rapidly progressive cancer of one of the following types of early (immature) bone marrow cells.
- Myeloblasts: form granulocytes.
- Monoblasts: converted to monocytes and macrophages.
- Erythroblasts: ripen to erythrocytes.
- Megakaryoblasts: become megakaryocytes, which form platelets.
Franco-American-British classification
The older Franco-American-British (FAB) classification system divides AML into subtypes based on the type of cells in which the leukemia began and how mature the cells are.
There are 8 subtypes of AML, ranging from M0 to M7.
- M0: Undifferentiated myeloid leukemia;
- M1: Myeloid leukemia with minimal maturation;
- M2: Fully maturing myeloid leukemia (the most common subtype of AML in children)
- M3: Promyelocytic leukemia;
- M4: Myelomonocytic leukemia (more common in children under 2 years of age);
- M5: Monocytic leukemia (more common in children under 2 years of age);
- M6: Erythrocytic leukemia;
- M7: Megakaryoblastic leukemia.
Subtypes M0 to M5 begin with immature leukocytes. AML M6 begins in immature forms of red blood cells, and AML M7 begins in immature cells that form platelets.
Classification by the World Health Organization (WHO)
The FAB classification system is still widely used to group AML into subtypes. But it does not take into account other factors that affect the prognosis, such as changes in chromosomes in abnormal cells.
AML is divided into several groups according to the WHO classification system.
- AML with certain genetic abnormalities:
- AML with a translocation between chromosomes 8 and 21;
- AML with translocation or inversion on chromosome 16;
- AML with translocation between chromosomes 9 and 11;
- AML (M3) with a translocation between chromosomes 15 and 17;
- AML with translocation between chromosomes 6 and 9;
- AML with translocation or inversion on chromosome 3;
- AML (M7) with a translocation between chromosomes 1 and 22.
- AML with myelodysplasia-related changes (congenital underdevelopment of the spinal cord).
- AML associated with previous chemotherapy or radiation exposure.
- Nonspecific AML (this includes AML cases that do not fall into one of the above groups and are similar to the FAB classification):
- AML with minimal differentiation (M0);
- AML without signs of maturation (M1);
- AML with signs of maturation (M2);
- myelomonocytic leukemia (M4);
- monocytic leukemia (M5);
- erythrocytic leukemia (M6);
- megakaryoblastic leukemia (M7);
- basophilic leukemia;
- panmyelosis with myelofibrosis.
- Myeloid sarcoma.
- AML associated with Down syndrome.
- Undifferentiated and biphenotypic acute leukemias (have lymphoblastic and myeloid features).
Stages of acute leukemia
There are four stages:
- initial (pre-leukemic);
- sharp;
- remission;
- terminal.
| Stage | Signs of leukemia in children |
| Initial (pre-leukemic) | Symptoms are nonspecific: increased fatigue, decreased appetite, headache, sometimes pain in the abdomen, bones and joints. Periodic unreasonable increase in temperature - from subfebrile to high values (37.4 - 39.2 0С). In some cases, an important symptom is noted - long bleeding after tooth extraction, in connection with which a blood test is prescribed and referred to a hematologist. In the analysis of blood - anemia, granulocytopenia, thrombocytopenia (lack of the corresponding blood elements). Duration - an average of 1.5 - 2 months. |
| Acute | Intoxication syndrome - weakness, lethargy, fatigue, inappropriate behavior, pale earthy skin, pain in bones and joints, fever, etc. |
| Proliferative syndrome: swelling of peripheral lymph nodes, the nodes are dense, painless. | |
| Mikulich's syndrome - a symmetrical increase in the lacrimal and salivary glands due to proliferation (proliferation) and infiltration (penetration of cells into an inappropriate environment) of lymphatic tissue; hepato- and splenomegaly (enlargement of the liver and spleen, respectively); leukemides are painless lumps on the skin of a bluish color, often located on the head. | |
| Anemic syndrome due to blast (the most immature cells) infiltration of the bone marrow with suppression of all hematopoietic germs: pale skin and mucous membranes, noise in the head, headache, loss of consciousness. | |
| Hemorrhagic syndrome due to thrombocytopenia, hemorrhages on the mucous membranes and skin: nosebleeds, melena (tarry stools), hematruia (blood in the urine). | |
| Neuroleukemia due to blast cell infiltration of the membranes of the brain and damage to the main structures of the central nervous system: headache, vomiting, hardness of the muscles of the occiput. Typical signs of cranial nerve damage; increased intracranial pressure. | |
| Rare signs: testicular infiltration in boys, ovaries in girls, damage to the skeletal system, etc. | |
| Remission | Against the background of polychemotherapy, remission occurs more often, which is considered complete in the absence of clinical, laboratory symptoms of the disease and foci of leukemia. |
| Relapses | Early, occurring up to 6 months after the end of the combined treatment, late, detected later than 6 months after the end of therapy. |
| Terminal | Complete suppression of normal hematopoiesis appears multiple infiltrates of internal organs, decompensated functional state of the body, infectious complications, resulting in a lethal outcome. |
Chronic myeloid leukemia (CML)
It is a slowly progressive cancer of early (immature) bone marrow myeloid cells. CML is not common in children, but it can still occur.
The course of CML is divided into 3 phases based on the number of immature leukocytes - myeloblasts ("blasts"), which are found in the blood or bone marrow.
If left untreated, leukemia can progress to a more severe condition over time.
Chronic phase
This is the earliest phase when patients usually have less than 10% blasts in their blood or bone marrow samples. These children have fairly mild symptoms (if any), and leukemia usually responds well to standard treatments. Most patients are in the chronic phase when they are diagnosed with the disease.
Accelerated phase
During this phase, the patient's bone marrow or blood samples have more than 10% but less than 20% blasts, or some other blood cell levels are very high or too low.
Children in the accelerated phase of CML may have symptoms such as fever, night sweats, poor appetite, and weight loss. In this phase, CML does not respond as well to treatment as in the chronic phase.
Explosion phase (acute phase)
At this stage, the bone marrow and / or blood samples have more than 20% blasts. Blast cells often spread to tissues and organs outside the bone marrow. These children often have fever, poor appetite, and weight loss. At this stage, CML acts as aggressive acute leukemia (AML or, less commonly, ALL).
Conditions similar to acute leukemia
Leukemoid reaction - an abnormal change in the composition of the blood, similar to a leukemic blood picture, but the pathogenesis is not associated with this disorder.
Leukemoid reactions can be of two types.
| Reaction type | Etiology |
| Myeloid type | They cause various infectious diseases - sepsis, tuberculosis, purulent processes, croupous inflammation of the lungs, mumps, scarlet fever, dysentery, intoxication, Hodgkin's lymphoma, tumor metastases in the bone marrow, radiation therapy. |
| Eosinophilic leukocytosis: helminthiasis (ascariasis, especially at the stage of migration, opisthorchiasis, trichinosis, etc.), allergic disorders (atopic pathology, collagenosis (damage to connective tissue), rheumatism). | |
| Lymphatic and monocytic-lymphatic type. | Whooping cough, chickenpox, rubella, scarlet fever, tuberculosis intoxication, foodborne diseases and poisoning. |
Treatment should be aimed at eliminating the underlying disorder that accompanies the leukemoid reaction.
Symptoms of leukemia in children
Many of the signs of leukemia in children can occur for other reasons. But if the child has any of the symptoms of this pathology, it is important that he is examined by a doctor.
The manifestations of leukemia are often accompanied by abnormalities in the bone marrow, where the disease begins. Cancer cells accumulate in the bone marrow and can crowd out healthy cells that produce blood cells. As a result, the child has a lack of healthy red blood cells, white blood cells and platelets.
These abnormalities show up on blood tests, but they also lead to symptoms. Often leukemia cells invade other areas of the body, this also causes the characteristic manifestations of the disease.
Symptoms of a low red blood cell count (anemia):
- fatigue;
- weakness;
- feeling cold;
- dizziness;
- headache;
- dyspnea;
- pale skin.
Symptoms with a reduced white blood cell count:
- diseases can occur due to a lack of normal white blood cells. Children with leukemia get infections that cannot be eradicated, or they get sick too often. Affected children often have high white blood cell counts, with so many cancer cells, but they do not protect against disease as healthy white blood cells do;
- fever is often the main symptom of infection, but some children may have a fever without infection.
Thrombocytopenia leads to:
- easy bruising and bleeding;
- frequent or severe nosebleeds;
- bleeding gums.
Sore bones or joints: it is caused by the accumulation of leukemia cells near the surface of a bone or inside a joint.
Increase in the size of the abdomen: cancer cells can accumulate in the liver and spleen, causing them to become enlarged.
Loss of appetite and weight: if the spleen and / or liver becomes large enough, they can press on the stomach. This makes you feel full after eating even a small amount of food. As a result, the child loses appetite and weight loss over time. In addition, the affected cells themselves are toxic to the body, leading to loss of appetite.
Swollen lymph nodes: sometimes leukemia spread to the lymph nodes. Swollen nodules are small lumps under the skin in certain areas of the body (for example, on the sides of the neck, in the armpits, above the collarbone, or in the groin). Lymph nodes inside the chest or abdominal cavity may also enlarge, but they can only be identified using instrumental research methods.
Cough or difficulty breathing: Certain types of leukemia can affect structures in the middle of the chest: lymph nodes or thymus. An enlarged thymus or lymph nodes in the chest press against the trachea, causing a cough or difficulty breathing. Sometimes, when the white blood cell count is very high, cancer cells accumulate in small pulmonary blood vessels, which can also lead to breathing problems.
Swelling of the face and hands: the superior vena cava, a large vein that carries blood from the head and arms back to the heart, runs near the thymus. The swollen thymus presses on this vein, forcing the blood to "rise" in the vessels. This phenomenon is called vena cava syndrome. Swelling of the face, neck, arms, and upper chest (sometimes with a blue-red skin color) occurs. Headaches, dizziness, and altered consciousness may also appear if the condition affects the brain. This syndrome can be life threatening and must be treated right away.
Headache, vomiting, convulsions: in a few children, leukemia spreads to the spinal cord and brain. This leads to headaches, trouble keeping attention, weakness, seizures, vomiting, imbalance, and blurred vision.
Rash, gum problems: In AML, leukemia cells can spread to the gums, causing them to swell, hurt, and bleed. If they spread to the skin, small, dark, rash-like patches may appear.
Fatigue, weakness: A rare consequence of AML is fatigue, weakness, and choppy speech. This happens when many leukemia cells make the blood very thick and blood circulation through the small blood vessels in the brain slows down.
Diagnosis of leukemia in children
It is important to diagnose and determine the type of leukemia in your child as early as possible in order to tailor treatment for the best chance of success.
History taking and physical examination
The doctor should ask the parents about the symptoms present and about their duration. It is also necessary to identify possible risk factors. Information about cancer among family members is equally important.
Physical examination should look for enlarged lymph nodes, areas of bleeding or bruising, or possible signs of infection. The doctor will carefully examine the eyes, mouth, and skin. The abdomen will be palpated to look for signs of enlarged spleen or liver.
Tests to detect leukemia
If leukemia is suspected, blood and bone marrow samples should be tested for the presence of leukemic cells.
Blood test
A complete blood count is done to determine the number of blood cells of each type. Their abnormal number may indicate leukemia.
Many affected children will have an excess of white blood cells and a lack of red blood cells and / or platelets. Many white blood cells will be immature.
Bone marrow biopsy
A small piece of bone and bone marrow is removed with a small needle to check for leukemia cells.
This method is used not only to diagnose a disease, the procedure is repeated later to determine if the disease is responding to treatment.
Lumbar puncture
This test is used to look for cancer cells in the CSF.
A small hollow needle is placed between the bones of the spine to remove some of the fluid.
Laboratory tests for the diagnosis and classification of leukemia
Microscopic examination
As mentioned above, blood tests are the first tests where leukemia is considered a possible diagnosis. Any other specimens taken (bone marrow, lymph node tissue, or CSF) are also viewed under a microscope. Samples may be exposed to chemical dyes that cause color changes in certain types of cancer cells.
In a blood sample, a specialist determines the size, shape, and color of cells in order to rank them.
The key point is whether the cells are mature. A large number of immature cells in a sample is a typical sign of leukemia.
An important feature of a bone marrow sample is the volume of cellular contents. Healthy bone marrow contains a certain number of blood-producing and fat cells. Bone marrow with too many hematopoietic cells is hyperplastic. If too few hematopoietic cells are found, this indicates hypoplasia.
Flow cytometry and immunohistochemistry
These tests are used to classify leukemic cells based on specific proteins in / or on them. This type of testing is very helpful in identifying the exact type of pathology. Most often, this is done on cells from the bone marrow, but tests can be done on blood cells, lymph nodes, and other body fluids.
For flow cytometry and immunohistochemistry, cell samples are processed with antibodies that attach to specific proteins. The cells are then examined to see if antibodies adhere to them (which means they have these proteins).
Flow cytometry can be used to estimate the amount of DNA in leukemic cells. This is important to know, especially in ALL, because cells with more DNA than usual are often more susceptible to chemotherapy and these leukemias have a better prognosis.
Chromosome research
Identification of certain chromosomal changes will make it possible to establish the type of acute leukemia.
In certain types of leukemia, the cells contain an abnormal number of chromosomes (their absence or the presence of an additional copy). It can also affect the forecast. For example, in ALL, chemotherapy is more likely to be effective if the cells have more than 50 chromosomes, and less effective if the cells have fewer than 46 chromosomes.
Cytogenetic research
Leukemic cells are grown in laboratory tubes and the chromosomes are examined under a microscope to detect any changes.
Not all chromosomal changes are found under the microscope. Other laboratory methods can help identify them.
Fluorescent in situ hybridization
DNA fragments are used that attach only to specific regions of certain chromosomes. The DNA combines with fluorescent dyes that can be seen with a special microscope. This study allows you to find most of the changes in chromosomes that are not visible under a microscope in standard cytogenetic tests, as well as some too small changes.
The test is very accurate and can usually produce results within a few days.
Polymerase chain reaction (PCR)
This is a very accurate test to detect some chromosome changes that are too small, even if there were very few leukemia cells in the sample. This test is very useful when looking for small numbers of cancer cells (minimally residual disease) during and after treatment that cannot be found on other tests.
Other blood tests
In children with leukemia, more tests need to be done to measure certain chemicals in the blood to check how well their body systems are working.
These tests are not used to diagnose cancer, but if leukemia is already diagnosed, they can detect damage to the liver, kidneys, or other organs caused by the spread of cancer cells or certain chemotherapy medications. Tests are also often done to measure the levels of important minerals in the blood and to monitor blood clotting.
Children should also be tested for blood infections. It is important to diagnose and treat them quickly because a child's weakened immune system will easily allow infections to spread.
Visual research methods
Leukemia does not form a tumor, so medical imaging is not as useful as it is for other types of cancer. But if leukemia is suspected or has already been diagnosed, these methods will help to better understand the extent of the disease or detect other problems.
Methods include:
- x-ray;
- CT scan;
- MRI;
- Ultrasound.
Leukemia treatment regimen
Chemotherapy
Chemotherapy is the main treatment for almost all leukemia. It involves therapy with anti-cancer drugs that are injected into a vein, muscle, CSF, or taken in tablet form. Except when they enter the CSF, chemicals enter the bloodstream and reach all areas of the body.
Combinations of several chemotherapy drugs are used to treat leukemia. Doctors administer chemotherapy in cycles, with each period followed by a rest phase to give the body time to recover. In general, AML is treated with higher doses of drugs for a short period of time (usually less than one year), and treatment for ALL includes lower doses of drugs for a long time interval (usually 2 to 3 years).
Radiation therapy
Radiation therapy uses high-energy radiation to kill cancer cells. This is not always necessary, but it can be used in different situations.
Radiation to the whole body is often an important part of the treatment before stem cell transplantation.
External beam radiation therapy, in which a device directs a radioactive beam to a specific part of the body, is most often used for leukemia in children.
The treatment itself is very similar to an X-ray examination, but the radiation is more intense.
Immunotherapy
Immunotherapy involves the use of drugs that can help the patient's own immune system more effectively identify and destroy leukemia cells. Several types of immunotherapy are being studied for use against leukemia, and some are already being used.
Chimeric antigen receptor T-cell therapy (CAR T-cell therapy).
For this treatment, immune T cells are removed from the child's blood and genetically altered in the laboratory (on their surface there are specific elements - chimeric antigen receptors (CHAR)). These receptors can bind to proteins on leukemic cells. T cells multiply in the laboratory and return to the child's bloodstream, where they can look for abnormal cells and attack them.
Most of the children undergoing this procedure did not show leukemia for several months of treatment, although it is not clear whether they have fully recovered or not.
High-dose chemotherapy and stem cell transplant
Stem cell transplants are sometimes done for children whose chances of recovery are low after standard or even intensive chemotherapy. High-dose therapy destroys the bone marrow, where new blood cells are formed. Transplantation after chemotherapy restores blood-producing stem cells.
The blood-forming stem cells used for leukemia transplants can be harvested from either blood or bone marrow from a donor. Sometimes, stem cells from the baby's umbilical cord blood taken at birth are used.
The donor tissue type should be as close as possible to the patient's tissue type to prevent the risk of severe transplant problems.
The donor is usually a brother or sister with the same tissue type as the patient. Rarely is it a compatible, unrelated donor. Umbilical cord stem cells are sometimes used. They are taken from the umbilical cord or placental blood obtained after the birth of a child. This blood is rich in stem cells.
The transplant is carried out several months after the onset of remission.
Treatment stages
| Stage | goal |
| Induction | Remission is achieved: in the bone marrow there are less than 5% of immature cells, their absence in the peripheral (outside the hematopoietic organs) blood. Signs of healthy hematopoiesis restoration. |
| Consolidation (fixation) of remission | Remnants of abnormal immature cells are eliminated. |
| Supportive care | Maintenance of remission, i.e. to reduce the likelihood of relapse after the previous two stages. |
How often does complete healing occur?
When analyzing survival statistics, doctors often use the concept of 5-year survival. This applies to patients surviving at least 5 years after cancer diagnosis. In acute leukemia, children who do not suffer from this disease after 5 years are most likely to recover completely, because it is very rare for leukemia to return after such a long period.
The likelihood of survival is based on previous results from a large number of children affected by cancer, but they do not predict what will happen to a particular child. Knowing the type of leukemia is important in assessing your outlook. But a number of other factors can also influence the prognosis. However, survival rates are approximate. Your child's doctor is likely to be a good source of whether this number applies to your child, as he or she knows your situation better.
Although survival rates have improved significantly over the past few decades, leukemia remains one of the leading causes of death in children (among diseases).
Five-year survival rates for all types of leukemia in children increased from 33% to 79% between 1971 and 2000.
Criteria for a favorable outcome. What determines success
Criteria for children with ALL
Children with ALL are often divided into risk groups (low, medium and high). Generally, low-risk patients have a better prognosis.
It is important to know that even children with some poor prognostic conditions can be fully recovered.
Age at diagnosis: children 1 to 9 years old with B-cell ALL have better cure rates. Children under 1 year old and over 10 years old are considered high-risk patients. The outlook for T-cell ALL is not strongly age dependent.
Initial leukocyte count: Children with ALL who have very high white blood cell counts (more than 50,000 cells per cubic millimeter) at diagnosis are at high risk and need more intensive treatment.
ALL subtype: the prognosis of ALL with immature B cell proliferation is usually better than that of mature cell proliferation. The outlook for T-cell ALL is about the same as for B-cell ALL, if treatment is intense enough.
Floor: girls with ALL have a slightly higher chance of being cured than boys. As treatment has improved in recent years, this difference has narrowed.
Extension to specific organs: the spread of leukemic cells to the cerebrospinal fluid or testicles in boys reduces the likelihood of a cure. Enlargement of the spleen and liver is usually associated with a high white blood cell count, but some experts see this as a separate sign of poor outcome.
Number of chromosomes: patients are more likely to be cured if their leukemia cells have more than 50 chromosomes, especially if they have an extra chromosome 4, 10, or 17. Children whose cancer cells contain fewer than 46 chromosomes have less favorable outlook.
Chromosomal translocations: children whose leukemia cells have a translocation between chromosomes 12 and 21 are more likely to be cured. Those with a translocation between chromosomes 9 and 22, 1 and 19, or 4 and 11 have a less favorable prognosis. Some of these "weak" predictive conditions have become less important in recent years as treatment has improved.
Reaction to therapy: children who have a marked improvement in the course of treatment (significant reduction of cancer cells in the bone marrow) within 1-2 weeks of chemotherapy have a better prognosis. In the absence of positive improvement, more intensive chemotherapy may be prescribed.
Criteria for AML
Age at diagnosis: AML in a child under 2 years of age responds better to treatment than older children (especially adolescents), although age does not have a strong impact on prospects.
Initial leukocyte count: children with AML who have less than 100,000 cells per cubic millimeter (WBC) at diagnosis are cured more often than patients with higher rates.
Down syndrome: the prognosis of AML in children with this syndrome is favorable, especially if the child is not more than 4 years old at the time of diagnosis.
AML subtype: acute promyelocytic leukemia (APL subtype M3) has a good prognosis, while undifferentiated AML (M0) and acute megakaryoblastic leukemia (M7) are more difficult to treat.
Chromosome changes: children with translocations in leukemia cells between chromosomes 15 and 17 (observed in most cases of APL) or between 8 and 21, or with inversion (rearrangement) of chromosome 16 are more likely to be cured. When a copy of chromosome 7 (monosomy 7) is missing from the abnormal cells, the outlook is less favorable.
Secondary AML: if you have leukemia from treatment with another cancer, the prognosis is less favorable.
Relapse
Sometimes, even when the baby is receiving optimal care, the leukemia cells return. Relapse can occur while the child is still receiving treatment or after therapy ends.
It is more difficult to achieve remission of recurrent leukemia than the primary disease. Treatment may include further chemotherapy, bone marrow transplantation, and / or experimental therapy.
Tips for parents if a teenager is sick
- Be honest and give your child details of their illness.
- Encourage your child to talk to you about their fears and concerns. Answer his questions honestly.
- When the child is hospitalized, stay in touch by phone, email.
- Let the child know why doctors and nurses are doing any tests or procedures.
- Let your child stay in touch with his friends using the phone, personal hospital visits, letters, photos and emails.
- Ask your child's teacher to visit, write a personal note, or make a phone call.
- It is important for the child to feel that he is in control of the situation. Therefore, let him make a choice - which pill to take first, which movie to watch, which book to read and what food to eat.
Conclusion
In most cases, leukemia in children has very high remission rates - up to 90%. However, the survival rate differs depending on the type of disease.
Children with leukemia face not only health problems, but also psychological and social difficulties. Therefore, such children need to be given a lot of attention, love and care so that they can lead a normal life like others.
