Leukemia describes a group of blood diseases characterized by the dysfunctional production and development of lymphocytes, a type of white blood cell (white blood cell) cells involved in body defense.
Blood cancer, a type of cancer that can be seen at any age, is a more common disease in children and adults over 50 years of age. It is of great importance that the disease, which has a high chance of treatment with early diagnosis, is recognized in the early stages and treatment is started.
What is leukemia?
Leukemia can be expressed as blood cancer in its simplest terms. Blood cancer, which occurs as a result of the development of stem cells in the bone marrow due to various reasons and uncontrolled proliferation, can spread primarily to the bone marrow and then to all organs.
Bone marrow is a spongy tissue made of red blood cells, white blood cells such as lymphocytes, and blood cells such as platelets (thrombocytes). After these cells are made in the bone marrow, they mix with the blood. White blood cells are one of the most important parts of the immune system. On the one hand, they protect the body against the invasion of viruses and foreign microorganisms such as bacteria, fungi or parasites, on the other hand, they detect cells that tend to become cancerous in the body and ensure their elimination.
Unlike other cells produced in the bone marrow, white blood cells can also be produced in various other organs such as the lymph node, spleen, and thymus.
Leukemia, which is a progressive disease that causes serious problems if left untreated, follows a slower course if it develops due to the uncontrolled increase in maturing white blood cells.
Bone marrow cancer, which develops due to the uncontrolled production of immature white blood cells, progresses rapidly and may cause clinical findings within 1-2 months.
What are the types of leukemia?
According to the course of the disease, blood cancer is divided into two as acute and chronic. The type of leukemia that progresses rapidly and gives clinical signs and symptoms in a short time is called acute, and the type of leukemia that progresses slowly and develops over many years is called chronic leukemia.
Cancer cells in acute leukemias are less mature, proliferating, and rapidly leaving the bone marrow dysfunctional compared to cancer cells in chronic leukemias. These dysfunctional cells are called blasts. As a result of rapid proliferation of blast cells in acute leukemias, it also invades the necessary living spaces for other healthy cells in the bone marrow, causing symptoms to occur in a short time.
Both types of leukemia are divided into two branches according to the type of white blood cell. If the white blood cell is myelocyte, it is defined as myeloid leukemia, and if the lymphocyte is lymphoblastic leukemia. In addition to these types of leukemia, there are different types of leukemia such as juvenile myelomonocytic leukemia, chronic myelomonocytic leukemia, myelodysplastic syndrome, myeloproliferative diseases and hairy cell leukemia, which are much less common.
Adults commonly have acute myeloid and chronic lymphocytic leukemia. Leukemia in children usually manifests as myeloid and acute myeloid leukemia (AML). Acute leukemia is a term used to express bone marrow cancer characterized by leukocytes that have not fully developed.
Leukemias are generally examined in 4 basic sub-categories:
- Acute Lymphoblastic Leukemia (ALL)
ALL is a type of blood cancer that occurs as a result of uncontrolled proliferation of primitive and lymphoid origin white blood cells (blasts) without completing their development. Approximately 80% of pediatric leukemia patients are in this group. For adults, this rate is around 20%. In this type of leukemia, the 5-year survival rate is defined as 68%.
- Acute Myeloid Leukemia (AML)
AML, which occurs as a result of uncontrolled proliferation of myelocytic blasts, is responsible for approximately half of the leukemias detected, especially in young people in their early 20s. AML is the most common type of acute leukemia in adults. The 5-year survival rate for this type of lymph cancer is around 26%.
- Chronic Lymphocytic Leukemia (CLL)
CLL results in the uncontrolled proliferation of lymphoid-derived white blood cells after completing their maturation. These cells are nonfunctional, and CLL most commonly occurs in individuals between the ages of 60 and 70. The predicted 5-year survival rate for this type of leukemia is 83%.
- Chronic Myeloid Leukemia (CML)
CML, which is a type of blood cancer that especially affects individuals between the ages of 25-60, occurs after the proliferation of myeloid cells. The 5-year survival rate for this type of leukemia is 67%.
What are the symptoms of leukemia?
The most prominent findings of leukemia, which are similar to the symptoms of other bone marrow diseases, include weakness, pallor, fatigue and shortness of breath due to anemia.
Symptoms of leukemia include infections caused by the weakened immune system and bleeding from the nose, teeth and gums, unexpected bleeding under the skin, bruising, and red rashes in the size of a pinhead (petechiae) on the skin.
Anorexia, weight loss, night sweats, febrile infections that cannot be controlled with treatment, bone pain, enlargement of the neck and axillary lymph nodes, swelling in the gums and abdomen, are the symptoms considered to be among the symptoms of acute leukemia.
- Leukemia Symptoms in Children
Leukemia, which constitutes approximately 30% of the cancer types seen in childhood, is more common in children between the ages of 2-5 and 5-10 years. Newborn babies use the immune support they receive from breast milk in the first 6 – 8 months of their life, and after this period, they regulate their own immune system until the age of 2 years. Viral infections during this period may trigger leukemia cancer.
Rickets occurring at this age and vitamin D deficiency due to this disease play a supportive role in the formation of blood cancer. For this reason, it is very important to expose children to the sun in suitable weather conditions and at the hours recommended by their doctor.
Common symptoms of leukemia in children:
- a pale skin color
- Loss of appetite and rapid weight loss
- Prolonged febrile infections
- Formation of bruises or glands on the body
- swelling in the abdomen
- Joint Pains
During the course of leukemia, some symptoms may occur as a result of involvement of tissues and organs other than bone marrow. For example, various symptoms such as headache, nausea, vomiting and seizures may occur after cancer metastasizes (splash) to the central nervous system.
Apart from the central nervous system, leukemia may spread to the lungs, digestive tract, heart, kidneys and testicles and cause complaints specific to these regions.
What causes leukemia, what are the risk factors?
Leukemia is a malignant disease that ranks 15th in the frequency of diagnosed cancer diseases. It ranks 11th in cancer-related deaths. It is 1.5 times more common in men than women, and leukemia tends to be more fatal in male patients. Depending on the type of leukemia, the cause and risk factors may vary.
RISK FACTORS FOR ACUTE LYMPHOBLASTIC LEUKEMIA
ALL is a type of leukemia whose underlying cause has not been definitively revealed. There is a predisposition to ALL type leukemia due to the high radiation generated in people living in areas close to nuclear explosion sites. The most important group to be careful about radiation exposure is the expectant mothers.
Chemicals such as benzene in cigarette smoke and various chemotherapy drugs used in cancer treatment are also considered among the conditions associated with the development of ALL type leukemia.
There is an increased risk of developing ALL in people infected with HTLV-1 and EBV viruses. Apart from infectious diseases, people with Down syndrome, Klinefelter syndrome, fanconi anemia and neurofibromatosis have an increased risk of ALL.
RISK FACTORS FOR ACUTE MYELOID LEUKEMIA
AML is a type of leukemia that occurs as a result of mutations and abnormalities in the DNA parts of the stem cells found in the bone marrow related to development and division. The likelihood of a person developing AML increases with age. The average age of diagnosis for AML is 68. For AML, which is more common in men, exposure to cigarette smoke, myelodysplastic syndrome and down syndrome are considered risk factors.
RISK FACTORS FOR CHRONIC LYMPHOCYTIC LEUKEMIA
Today, the exact underlying cause of CLL development has not been revealed yet, but being over 50 years old, male gender, exposure to chemical agents used in wars, and the presence of other individuals in the family with this disease are considered risk factors for the development of CLL.
RISK FACTORS FOR CHRONIC MYELOID LEUKEMIA
CML is a type of leukemia caused by genetic mutations, but what or what triggers these mutations is not yet fully understood. These genetic mutations are abnormalities that occur later in an individual’s life. A person does not inherit the genes associated with this disease from their parents.
Humans have a total of 23 pairs of chromosomes. With the changes in parts between chromosomes 22 and 9, chromosome 22 becomes shorter than normal and chromosome 9 becomes longer than normal.
The mutated chromosome 22 is called the Philadelphia chromosome and can be detected in 90% of CML patients. The BCR-ABL gene on the Philadelphia chromosome triggers the uncontrolled proliferation of blood cells, causing the development of CML.
How is leukemia diagnosed?
The examinations to be requested and the applications to be made for the diagnosis of leukemia are numerous and very time-consuming. The purpose of using many tests is to reveal the type and stage of the disease exactly.
During the physical examination performed by the physician, the presence of signs indicating leukemia such as pale appearance due to anemia, enlarged lymph nodes, spleen and liver enlargement are examined.
Complete blood count, metabolic and biochemical values, liver function tests and coagulation values of the patient are among the useful tests in the diagnosis of leukemia. In addition to these tests, peripheral blood smear and bone marrow examination are important applications with diagnostic value for leukemia.
Bone marrow aspiration biopsy is a necessary and important test for the diagnosis of acute leukemia. In chronic leukemia, peripheral blood evaluation is generally considered adequate and further biopsy procedures may not be required in these individuals. In CML, the BCR-ABL gene can be detected using genetic diagnostic methods.
The bone marrow test is usually performed from the patient’s hip bone. The bone marrow sample taken from this bone is sent to the laboratory by means of a long needle and the presence of cancer cells is evaluated.
How is leukemia treated?
In order to treat leukemia, first of all, its type must be determined. A simple complete blood count detects signs of cancer in the blood. The diagnosis of leukemia is made due to the increase of cancer cells called blasts in the blood.
A biopsy from the bone marrow shows whether the bone marrow is involved with cancer cells. The important point in treatment is to determine the subtype of leukemia. The treatment method varies according to the subtypes of leukemia.
The first method that comes to mind in the treatment of leukemia is chemotherapy. Chemotherapy drugs are chemical drugs that destroy cancer cells that cause leukemia. Depending on the type of leukemia, the type, dose and route of administration of the drugs to be used in chemotherapy also vary.
Radiotherapy (radiation therapy) uses high-energy rays to destroy leukemia cells and prevent their growth. Radiation therapy can be applied to only part or all of the body. Radiotherapy is also a method used in preparation for stem cell transplantation.
With the use of biological agents and immunotherapy drugs in these patients, it is aimed to enable people’s own immune systems to recognize cancer cells. Defense cells, which detect malignant cells more frequently thanks to these drugs, ensure the elimination of cancer cells.
As it is generally accepted, bone marrow transplantation is one of the most effective treatment methods in leukemia patients. In this method, which is known as stem cell transplantation, marrow transplantation can be performed from the patient’s own healthy marrow or from siblings, close relatives or donors who provide tissue compatibility.
The purpose of bone marrow transplantation is to replace the diseased bone marrow in the person with healthy bone marrow. Before this procedure, high doses of chemotherapy and radiotherapy are given to the patient to completely eliminate the diseased bone marrow. Afterwards, the patient is infused with blood-forming stem cells and it is aimed to regenerate the healthy bone marrow.
Bone marrow transplantation is considered one of the major medical procedures and may cause side effects such as sudden blood pressure drop, headache, nausea, vomiting, pain, shortness of breath, fever and chills in the person to be transplanted. Apart from these symptoms, there are also more serious side effects of bone marrow transplantation. The occurrence of these serious side effects varies according to the age, general health status of the person, the disease he received the treatment for, and the type of transplantation.
GVHD (donor-to-recipient disease) is a major health condition that describes the way a donor’s blood cells struggle against cells in the recipient’s body. Apart from GVHD, transplant rejection and internal organ damage or bleeding are among the serious side effects that may occur after transplantation.
Treatment planning for leukemia is carried out by hematology oncology specialists. Treatment may vary depending on both the type of leukemia and patient-specific factors.
During chemotherapy treatment, it is very important to give supportive treatment in addition to these drugs, especially in acute leukemia patients. As a result of the effect of chemotherapy drugs on the normal blood cells of the patient, it increases the susceptibility to infectious diseases, bleeding and anemia. For this reason, in addition to chemotherapy treatment, antibiotic drugs and, if necessary, blood transfusion and other blood products can be transferred to the patient.
In addition to antibiotics, antifungal drugs and anti-nausea antiemetic drugs are among the drugs that can be prescribed to the patient by physicians when necessary.
Tyrosine kinase inhibitor drugs with imatinib active ingredient in CML patients , by acting against mutated genes and products, led to the emergence of a revolutionary treatment plan. Another important feature of these drugs is that they have fewer side effects than chemotherapy drugs.
Acute and chronic leukemias are diseases with complex diagnosis and treatment stages that include many types of blood diseases. Since the earlier the diagnosis is made, the higher the effectiveness of the treatment, it is important to be aware of these disorders. Although there is a decrease in death rates and an increase in survival rates in the light of new diagnosis and treatment methods as the years progress, leukemia is one of the diseases that should be considered because it is life-threatening.
While the 5-year cancer survival rate in people with leukemia was around 30% in 1975, this rate has increased to over 60% today. The biggest reason for this is awareness and early diagnosis. For this reason, if you encounter symptoms of leukemia in yourself and the people around you, it is recommended that you do not neglect to seek help from specialist physicians by applying to the nearest health institutions.