Leukemia

Leukemia is a type of cancer that develops in the white blood cells of the body. Leukemia is also known as blood cancer or bone marrow cancer. With 30 percent, leukemia is the most common among childhood cancers.

Leukemia is a disease that originates in the bone marrow. The bone marrow, a spongy structure found inside the bones, is where red and white blood cells (erythrocytes and leukocytes) and the platelets that enable blood clotting are produced.

The uncontrolled and excessive proliferation of the lymphoid and myeloid cells, which are among the white blood cells produced here, causes leukemia.

These abnormal white blood cells prevent healthy white blood cells, which help fight infections and diseases in the body, from working. This causes symptoms such as anemia, deficiency of the immune system, a tendency to bleed, pale skin and bruising.

Leukemia is the most common type of cancer in children under 15 years of age. However, it can also occur in adults over 55.

Today, recovery in childhood acute lymphoblastic leukemia (ALL) has reached 85-90 percent; in adult leukemias, success varies by type and age (about 30-35 percent in acute myeloid leukemia, AML). Many factors affecting treatment success contribute to this, such as the increased importance given to patient care, improved laboratory facilities and better determination of risk classification.

Bone marrow (stem cell) transplantation is preferred in leukemias that do not benefit from chemotherapy and in relapsed leukemias.

 

Types;

Leukemias are classified in two ways according to the type and progression of the disease:

-Myeloid or lymphoblastic

Lymphocytes or myeloblasts, according to the white blood cells in which the cancer first appears.

-Lymphocytes

They mostly fight viral infections.

-Myeloid cells

They perform a range of different functions, such as fighting bacterial infections, defending the body against parasites and preventing the spread of tissue damage.

-Acute or chronic

In the acute type, symptoms appear suddenly and worsen rapidly. In the chronic type, symptoms appear over years and progress slowly. Most childhood leukemias are acute; in adults, chronic leukemias (especially chronic lymphocytic leukemia, CLL) make up about half of all leukemias.

 

Based on these classifications, the disease is grouped into 4 types:

-Acute myeloid leukemia (AML)

It is the most common type of acute leukemia.

-Acute lymphoblastic leukemia (ALL)

It is a fast-progressing type of leukemia seen most often in children under 15 and, rarely, in adults over 45.

-Chronic myeloid leukemia (CML)

It usually progresses slowly but can sometimes become acute.

-Chronic lymphocytic leukemia (CLL)

It is a cancer that generally develops slowly and begins in the bone marrow before the bloodstream.

Treatment for patients with leukemia depends on whether the leukemia is acute or chronic and on the type of blood cell affected.

 

Causes of Leukemia

In 90 percent of leukemia patients, no underlying cause is identified. However, in 10 percent, radiotherapy or chemotherapy received earlier for other reasons, exposure to chemical agents, or certain congenital conditions such as Down syndrome can create a predisposition to leukemia.

The causes of leukemia in children  do not depend on environmental factors as they do in adults. While factors such as smoking and alcohol use, exposure to chemicals, infections and diet cause cancer in adults, leukemia in children usually arises from genetic causes.

Viruses such as Epstein-Barr, which causes mononucleosis, can also cause leukemia. In addition, leukemia may occur in children working in industrial sectors where petrochemical products such as ‘benzene’ are used.

 

Symptoms of Leukemia

Leukemia, which can be seen at any age from the newborn period to adolescence, most often threatens children between 2 and 5 years of age. It is important for parents to take symptoms such as anemia and bruising seriously and to consult a physician.

Bruises seen in a child should be taken seriously and a doctor should be consulted in the following situations.

1. If they are on soft areas of the body,
2. If they are disproportionately large for the force of the blow,
3. Or if they occur without any blow at all.

In the physical examination performed by the doctor, local or widespread enlargement of the bruises is an important finding.

If, in addition to bruises, there is enlargement of the liver and spleen, the child's general health is poor, and not only the platelets but also other blood cell values in the blood count, for example the white blood cells, are affected, and the red blood cells and hemoglobin are low, further investigations are carried out because of suspicion of an underlying cancer based on the overall picture.

Childhood cancers are among the diseases that can be treated and therefore, thanks to early diagnosis, the chance of complete recovery from the disease is very high.

 

Symptoms of Leukemia

1. Pale skin due to anemia
2. Easy bleeding and unexplained bruising due to a low platelet level 
3. Frequently recurring high fever, sweating and chills
4. Weakness, fatigue, tiring easily
5. Unexplained weight loss
6. Loss of appetite
7. Usually painless swelling of the lymph nodes in the neck, armpit and/or groin
8. Pain or bleeding in the gums
9. Nosebleeds
10. Pain in the bones or joints 
11. Leg pains of unknown cause in children
12. Very small red spots and bruises under the skin
13. Cough, chest pain, shortness of breath

The symptoms according to the types of leukemia are as follows;

-Symptoms of Acute Myeloblastic Leukemia

Weakness: due to anemia

1. Shortness of breath
2. Bruises on the skin
3. Tiring easily
4. Fever (due to infections)
5. Bone pain
6. Gum and nose bleeding

-Symptoms of Acute Lymphoblastic Leukemia

1. Weakness: due to anemia
2. Shortness of breath
3. Bruises on the skin
4. Enlargement of the liver, spleen and lymph nodes
5. Tiring easily
6. Fever: due to infections
7. Bone pain
8. Gum and nose bleeding

-Symptoms of Chronic Myelocytic Leukemia

1. Fatigue
2. Pain
3. Sweating

-Symptoms of Chronic Lymphocytic Leukemia

1. Weakness
2. Weight loss
3. Fever
4. Enlargement of the liver and spleen
5. Palpable swellings in the neck, armpits and groin
6. Tiring easily

 

Diagnostic Methods for Leukemia

Leukemia is diagnosed with a good patient history and physical examination. The patient usually presents to the doctor with weakness, fatigue, paleness, fever, enlarged lymph nodes, bruises on the body, and an enlarged liver and spleen.

After the examination, a complete blood count and a peripheral smear test are performed. In the peripheral smear test, the blood cells are examined under a microscope. Abnormal blood cells raise the suspicion of leukemia; the diagnosis is confirmed by bone marrow, flow cytometry and genetic tests.

However, since leukemia is a cancer that originates in the bone marrow , the definitive diagnosis is made by taking the bone marrow and examining it in the pathology, genetics and flow cytometry laboratories.

-Diagnosis of Acute Myeloblastic Leukemia

1. Peripheral smear
2. Bone marrow aspiration and, if necessary, bone marrow biopsy
3. Flow cytometry
4. Genetic tests

-Diagnosis of Acute Lymphoblastic Leukemia

1. Blood count
2. Peripheral smear
3. Bone marrow aspiration and, if necessary, biopsy
4. Flow cytometry
5. Genetic tests

-Diagnosis of Chronic Myelocytic Leukemia

1. Blood count
2. Peripheral smear
3. Bone marrow aspiration and biopsy
4. Genetic tests

-Diagnosis of Chronic Lymphocytic Leukemia 

1. Blood count
2. Peripheral smear
3. Flow cytometry
4. Bone marrow aspiration and biopsy
5. Genetic tests

 

Treatment Methods for Leukemia

After the diagnosis of leukemia, the disease is stratified into risk groups. More intensive and longer treatment is given to high-risk patients, and less intensive treatment to some patients.

Leukemia is treated primarily with chemotherapy drugs given intravenously and by mouth. Chemotherapy can also be given into the cerebrospinal fluid to protect the central nervous system or, if there is damage, to prevent it from spreading.

In addition to chemotherapy , blood and blood products, preventive and, when necessary, curative antimicrobial therapy, and treatments that support morale and mental health are effective in increasing the chance of success.

In addition, cancer drugs that strengthen the immune system (immunotherapy), radiotherapy and Car T Cell therapy are used depending on the patient's condition.

What Is Car T Cell Therapy?

Car T Cell therapy is a treatment that retargets the patient's immune system to fight cancer. It is based on changing the genetics of T cells, the main element of our cellular immune system, to convert our immune system cells that do not recognize cancer into cells that recognize and fight it.

Bone Marrow / Stem Cell Transplantation

It is a treatment model applied after very high-dose chemotherapy, primarily in leukemia but also in high-risk or relapsed lymphoma and solid tumors that are sensitive to chemotherapy. 

The bone marrow or stem cells used for transplantation may come from the patient themselves (autologous) or, as preferred especially in leukemias, from a donor with a matching tissue type (allogeneic). 

Today, bone marrow transplantation can also be performed with stem cells taken from the patient's sibling, mother, father or, if the patient is older, children. In this method, called haploidentical transplantation, the mismatched tissues in the collected stem cells are removed.

Although haploidentical bone marrow transplantation carries more risk than other types of transplantation, thanks to recent technological advances these risks are approaching those of fully matched transplants. 

Because of the very high-dose chemotherapy given before bone marrow transplantation , very important side effects such as tissue rejection, bleeding and infection can develop during the transplant and during the period until the tissue is accepted. Although bone marrow transplantation is a treatment model that increases the chance of recovery, there is a risk of the disease recurring.

 

Success of Treatment

In the most common acute leukemias, the curability rate can rise from 45 percent to 85 percent, varying according to the cell type and the risk group of the disease. In the remaining patients, there is a possibility of leukemia relapse.

Childhood cancer may also recur in adulthood. This rate is lower in leukemias and higher in some brain tumors and solid tumors. If the disease is caught at an early stage and diagnosed and treated before it metastasizes, the likelihood of relapse decreases. 

After treatment, leukemias are followed for 10 years. Check-ups are performed first every month, then at 3-month and annual intervals. The likelihood of relapse decreases as the years pass. Although very rare, there are patients who relapse after 10 years.

As the molecular genetic characteristics of the leukemia cell are determined through ongoing research, new targeted treatment models are being developed. Today, depending on the type of leukemia and the risk group, patients can regain their health with treatment lasting 2-3 years.

In disease that does not respond to the initial treatment, or that recurs after having responded, there is still a chance of recovery in some patients with bone marrow transplantation.

 

Types of Leukemia and Treatment Methods

-Acute Myeloblastic Leukemia

In the bone marrow, granulocytes and monocytes, which form the leukocytes that fight diseases, produce young (blast) cells in the bone marrow. These cells mature over time and play an important role in the immune system.

In acute myeloblastic leukemia , as a result of an abnormality in the maturation of young cells, cells that cannot continue their normal course accumulate in the blood and bone marrow and are unable to perform their function in the immune system. This clinical picture is called “Acute Myeloblastic Leukemia”.

Treatment Methods for Acute Myeloblastic Leukemia

1. Chemotherapy
2. Bone marrow (stem cell) transplantation is performed.

Acute Lymphoblastic Leukemia

Lymphocytes are the building blocks of the leukocytes in the body that play a role in the immune system. When these lymphocytes are young in the bone marrow, they are called lymphoblasts. It is a disease that occurs when the lymphoblasts in the bone marrow proliferate in an uncontrolled, abnormal and disorderly way without maturing, and are unable to produce lymphocytes, which are mature cells.

Treatment Methods for Acute Lymphoblastic Leukemia

1. Chemotherapy
2. Bone marrow (stem cell) transplantation
3. Car T Cell therapy

Chronic Myelocytic Leukemia

It is the presence in the blood of more mature cells than normal among the leukocytes that make up the immune system. In this type of cancer, in which genetic factors (the Philadelphia chromosome) play a role, white blood cells outnumber red blood cells and platelets.

Treatment Methods for Chronic Myelocytic Leukemia

1. Drug therapy
2. Bone marrow (stem cell) transplantation in resistant cases

Chronic Lymphocytic Leukemia

It is a type of cancer that occurs when the structure of the lymphocytes in the immune system is impaired and they accumulate in large numbers in the body. The structurally impaired lymphocytes cannot help the immune system and at the same time prevent the production of red blood cells and platelets.

Treatment Methods for Chronic Lymphocytic Leukemia

1. Chemotherapy and immunotherapy
2. Radiotherapy if necessary
3. Bone marrow (stem cell) transplantation if necessary