Chronic myeloid leukemia (CML) is a malignant disease of blood and bone marrow systems. Pathology develops when the patient’s bone marrow begins to produce a large number of defective cancer cells that replace normal blood cells. This leads to disruption of all blood system functions in the body.
Chronic myeloid leukemia is very rare among children; as a rule, this pathology affects the adult population. Every year in the United States, no more than 110-120 cases of this disease are recorded among children.
Specialists of Pediatric Hematology Oncology Department at Tel Aviv Medical Clinic offer their patients advanced and effective methods of CML treating in children, since our hematologists have unique experience in treating this disease among pediatric patients. Most of them have completed unique postgraduate education programs at the most renowned children’s hospitals in the world.
Specialists apply an individual approach to each child, taking into account both the characteristics of the disease itself and the patient. If a child requires a bone marrow transplantation, TAMC doctors use the services of National Bone Marrow Donation Program (the largest stem cell bank) to select an ideal donor (if a relative is not suitable).
Causes of CML in children
In 90-95% of cases, chronic myeloid leukemia has a genetic cause. In such patients, a typical mutation is detected – the Philadelphia chromosome (translocation between 9 and 22 pairs of chromosomes).
The disease is not inherited; each time it occurs anew (and randomly and sporadically).
Why this happens has not yet been established. Among the risk factors for Philadelphia chromosome formation, and then CML, are the negative effects of ionizing radiation, infectious agents action, various toxins, including medications.
Symptoms of CML in children
Unlike acute forms of leukemia, CML develops slowly and initially has no symptoms, often being diagnosed accidentally due to changes in blood tests taken for other reasons.
The most common symptoms of the disease are:
- Anemia and anemic syndrome manifestations. The bone marrow, which is overcrowded with pathological cells, is not able to produce the required number of red blood cells, which is why anemia develops. Children with anemia most often experience increased fatigue, rapid heartbeat, breath shortness, they lag behind their peers in physical development, and they have difficulties in school.
- Increased bleeding due to a lack of platelets in blood. Bone marrow also cannot produce the required number of platelets (cells that take part in blood clotting processes). In this case, bruises, hematomas, bleeding from gums, nosebleeds, etc. easily occur.
- Frequent infectious diseases, with complications (otitis, sinusitis, pneumonia).
- Prolonged elevated body temperature.
- Abdominal pain due to damage of abdominal lymph nodes.
- Enlarged spleen.
- Enlarged lymph nodes.
- Pain in bones and joints.
- Dyspnea.
Stages of chronic myeloid leukemia:
- Chronic phase. This is initial stage of the disease, in which up to 10% of blast cells are found in bone marrow. It has a long asymptomatic course (approximately 5-6 years), responds well to treatment and is characterized by a favorable prognosis. Occurs in approximately 94% of cases.
- Acceleration phase. At this stage, the number of blast cells in bone marrow is 10-30%. Primary CML at acceleration stage is diagnosed in 3-5% of cases. The response to treatment is slightly worse than in chronic phase.
- Blast crisis. This is the most aggressive CML stage, it occurs in 1-2% of cases. At the same time, the number of blasts in bone marrow exceeds 30%. The prognosis is ambiguous, and the response to treatment is usually incomplete.
Modern diagnostic methods
Pediatric Hematology Department at TAMC has a unique and innovative material and technical base, so the department is equipped with only the most modern diagnostic equipment, which allows for a comprehensive diagnostics in just 3-5 working days.
In complex diagnostics of CML in children, the following is used:
- Detailed medical examination and study of patient’s medical history.
- A set of necessary diagnostic blood tests (general blood count, biochemical, other hematological tests).
- Bone marrow puncture or biopsy. Used to confirm the diagnosis and determine CML phase. In children, it is performed only under general anesthesia so that the little patient does not feel pain or fear.
- Blood cells immunophenotyping is a study that allows us to determine the types of leukemia with a high accuracy degree.
- Cytogenetic analysis of blood cells is a modern technique for studying changes in chromosomes. An example is a modern technique – FISH analysis (fluorescence in situ hybridization).
- Molecular genetic testing to detect certain mutations associated with this disease, including the Philadelphia chromosome.
Other studies can be used to determine tumor extent (lumbar puncture, CT, MRI of brain, chest and abdominal organs, etc.).
Prognosis for chronic myeloid leukemia in children
With timely diagnosis – favorable. The 5-year survival rate is in 80-90%.
Modern treatment of CML in children
Treatment depends on the phase of chronic myeloid leukemia.
Important! Today, the “gold standard” for CML treating is targeted therapy. This type of blood disease is one of the first to be treated with targeted drugs.
The main targeted drugs for CML treatment are the so-called tyrosine kinase inhibitors (TKIs) – drugs that act on cells with the Philadelphia chromosome presence (imatinib, dasatinib, nilotinib and bozotinib).
Bone marrow transplantation from a donor (allogeneic) is currently no longer the main CML treatment method. It is used only in cases where the patient has resistance to TKI targeted drugs, as well as when diagnosing the disease at advanced stages.
Since the disease is highly treatable with targeted drugs, other innovative methods of immunobiological treatment of chronic myeloid leukemia in children, including CAR-T cell therapy, are not used. Recent studies have shown that the life expectancy of patients with chronic myeloid leukemia who receive modern targeted therapy is similar to that of the general population.
