What is chronic myeloid leukemia and how is it treated?

Chronic myeloid leukemia is a cancer of the blood, which is characterized by a decrease in the level of leukocytes and the appearance of a large number of immature cells - granulocytes.

According to statistics, the incidence of myeloid leukemia is the same in women and men, most often occurs at the age of 30-40 years.

Short information about chronic myeloid leukemia

The causes of chronic myeloid leukemia

Among the main factors provoking a cancer of the blood are:

- Hereditary predisposition - cases of blood cancer are recorded in relatives;
- Genetic predisposition - the presence of congenital chromosomal mutations, such as Down syndrome, increases the likelihood of the disease;
- Exposure to radiation;
- The use of chemotherapy and radiation therapy in the treatment of other cancers can provoke myeloid leukemia.

Stages of chronic myeloid leukemia

The development of chronic myeloid leukemia occurs in three successive stages:

- Chronic stage: The longest stage, which usually lasts 3-4 years. Most often, it is asymptomatic or with a blurred clinical picture, which does not cause suspicions about the cancerous nature of the disease either from doctors or patients. Chronic myeloid leukemia is detected, usually with a random blood test.
- Accelerative stage: At this stage, the disease becomes active, the level of abnormal blood cells increases at a rapid rate. The duration of the acceleration is about a year. At this stage, with the right therapy, there is a chance to return leukemia to the chronic stage.
- Terminal stage: The most acute stage lasts no more than 6 months and ends fatally. At this stage, blood cells are almost completely replaced by pathological granulocytes.

Chronic myeloid leukemia symptoms

The manifestations of the disease directly depend on the stage.

- Chronic stage symptoms:
In most cases, it is asymptomatic. Some patients complain of weakness, increased fatigue, but, as a rule, do not attach importance to this. At this stage, the disease is detected during the routine blood test. In some cases, weight loss, loss of appetite, increased sweating may occur, especially during a night's sleep.
With an increase in the spleen, pain in the left abdomen may occur, especially after eating.
In rare cases, a tendency to bleed develops due to a decrease in platelet levels. Or, on the contrary, when they increase, blood clots are formed, which is fraught with myocardial infarction, stroke, impaired vision and breathing, and headaches.
- Accelerative stage symptoms:
As a rule, it is at this stage that the first manifestations of the disease are felt. Patients complain of poor health, severe weakness, increased sweating and pain in joints and bones. Concerns about increased body temperature, increased bleeding and an increase in the abdomen due to the growth of tumor tissue in the spleen.

Diagnostics of the chronic myeloid leukemia

Chronic myeloid leukemia is diagnosed by an oncologist-hematologist.

Blood tests

This is the main diagnostic method. It can be used not only to diagnose, but also to determine the stage of the pathological process.
At the chronic stage, in the general blood test, an increase in platelets and the appearance of granulocytes are noted against the background of a decrease in the total number of leukocytes.

At the accelerating stage, the share of granulocytes already accounts for 10-19% of leukocytes, the platelet content can be either increased or, on the contrary, decreased.

In the terminal stage, the number of granulocytes increases steadily, and the level of platelets falls.

A biochemical blood test is performed to analyze the functioning of the liver and spleen, which, as a rule, suffer from myeloid leukemia.

Bone marrow biopsy

For this study, the bone marrow is taken with a thin needle, after which the material is sent to the laboratory for detailed analysis.
Most often, the bone marrow is taken from the head of the femur, however, the calcaneus, sternum, wings of the pelvic bones can be used.

A picture similar to a blood test is observed in the bone marrow - the number of immature leukocytes increases.

Hybridization and PCR

A study such as hybridization is necessary in order to identify an abnormal chromosome, and PCR is an abnormal gene.

Cytochemical research

The essence of the study is that when special dyes are added to blood samples, certain reactions are observed. According to them, the doctor can not only determine the presence of a pathological process, but also carry out differential diagnostics between chronic myeloid leukemia and other variants of blood cancer.

In a cytochemical study in chronic myeloid leukemia, a decrease in alkaline phosphatase is observed.

Cytogenetic studies

This study is based on the study of the patient's genes and chromosomes. For this, blood is taken from the vein, which is sent for a special analysis. The result, as a rule, is ready only after a month.

In chronic myeloid leukemia, the so-called Philadelphia chromosome is found - the culprit for the development of the disease.

Instrumental research methods

Ultrasound, computed and magnetic resonance imaging are necessary for the diagnosis of metastases, the state of the brain and internal organs.

Treatment of chronic myeloid leukemia

Bone marrow transplantation gives a real chance of recovery for patients with chronic myeloid leukemia.

This treatment option consists of several successive stages:

Search for a bone marrow donor. Close relatives are the most suitable donor for transplantation. If a suitable candidate is not found among them, it is necessary to look for such a person in special donor banks.
After it is found, various compatibility tests are performed to make sure that the donor material will not be aggressively perceived by the patient's body.

Preparation of the patient for surgery lasts 1-1.5 weeks. At this time, the patient undergoes chemotherapy and radiation therapy.

Bone marrow transplantation. During the procedure, a catheter is inserted into the patient's vein, through which stem cells enter the bloodstream. They settle in the bone marrow and after a while begin to work there. For the prevention of the main complication - rejection - medications are prescribed to suppress the immune system and prevent inflammation.

Decreased immunity. It usually takes about a month from the moment the stem cells are introduced to the start of their work in the patient's body. At this time, under the influence of special drugs, the patient's immunity is reduced, this is necessary to prevent rejection. However, on the other hand, this creates a high risk of infection. The patient should spend this period in a hospital, in a special ward - he is protected from contact with a possible infection. Antifungal and antibacterial agents are prescribed, body temperature is constantly monitored.

Cell engraftment. The patient's well-being gradually begins to improve and return to normal.
Recovery of bone marrow function takes several months. During this entire period, the patient is under the supervision of a doctor.
Antiviral prophylaxis and a range of vaccinations are recommended to protect the immunocompromised body from infections.

Chemotherapy

In chronic myeloid leukemia, several groups of drugs are used:

- Hydroxyurea preparations that inhibit DNA synthesis in tumor cells. Side effects may include digestive disorders and allergies.
Of the modern drugs, protein tyrosine kinase inhibitors are often prescribed. These drugs inhibit the growth of abnormal cells, stimulate their death, and can be used at any stage of the disease. Side effects include cramps, muscle pain, diarrhea, and nausea.
- Interferon is prescribed after the normalization of the number of leukocytes in the blood to suppress the formation and growth and restore the patient's own immunity.
Possible side effects include depression, mood swings, weight loss, autoimmune pathologies and neuroses.

Radiation therapy

Radiation therapy for chronic myeloid leukemia is carried out in the absence of the effect of chemotherapy or in preparation for a bone marrow transplant. Gamma radiation of the spleen helps to inhibit tumor growth.

- Splenectomy. In rare cases, spleen removal or, in medical terms, splenectomy may be prescribed. The indications for this are a sharp decrease in platelets or severe abdominal pain, a significant increase in the organ or the threat of rupture.
- Leukocytophoresis. A significant increase in white blood cells can lead to serious complications such as microthrombosis and retinal edema. In order to prevent them, your doctor may prescribe leukocytapheresis.

This procedure is similar to conventional blood purification, only in this case tumor cells are removed from it. This improves the patient's condition and prevents complications. Leukocytophoresis can also be used in combination with chemotherapy to improve treatment response.

Post by: Natalie Keller, M.D. General Health Centre, Minneapolis, Minnesota