Leukemia is a relatively complex a challenging topic. Due to their difficult and hard to remember classification, I have decided to focus more on some general principles in leukemia causes, symptoms, diagnostic approach and therapy to make this issue understandable even for the laymen.
Leukemia is a name for a whole group of diseases that could be described as "blood cancers". The term comes from the Greek word “leukos” meaning “white”. This is because the tumor cells come from the white blood cells (leukocytes). White blood cells are produced in the bone marrow (and eventually in some other tissues) and they are necessary for proper function of the immune system. Under certain circumstances, a mutation occurs in a white blood cell causing its uncontrollable multiplication. If such cell is not recognized by the immune system as a threat and destroyed, it will produce a number of daughter cells (malignant clones) that spread throughout the body.
The cause of mutation is not always clear. Sometimes it is related to genetics, sometimes viral infection or exposure to certain chemical substances. Leukemia is relatively frequently found in children with Down syndrome.
Note: We distinguish acute (rapid onset and course) and chronic (slow onset and course) leukemia according to the speed of onset of its symptoms and its progress. According to the type of tumorous white blood cells we distinguish myeloid and lymphoblastic leukemia. The four basic types are combination of the above-mentioned terms: acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML) and chronic lymphoblastic leukemia (CLL). In addition, there are also other types of leukemia, but these are not so important for basic understanding.
The body of the patient is usually flooded with a number of tumorous white blood cells. These cells settle in the bone marrow, lymph nodes and organs of the body. This brings two fundamental complications. First, the cancer cells are immature and can not perform proper function of immune defense and in addition, the bone marrow invasion of tumor cells can suppress proper formation of healthy leukocytes, red blood cells and platelets.
The symptoms of leukemia are initially nonspecific (fatigue, fever, night sweats, joint pain, muscle pain, etc.). Furthermore, the patient may suffer from symptoms related to infestation of tissues by tumor cells (painless enlarged lymph nodes, enlarged liver, enlarged spleen, bone pain, etc.) and the lack of healthy blood cells and platelets. The lack of red blood cells manifests with anemia and anemic syndrome. Lack of functional white blood cells is followed by weakened immunity and recurrent infections and lack of platelets causes more frequent bleeding (bruising, nosebleeds, blood in stool, blood in urine, etc.). The death in leukemia is usually related to infectious or bleeding complications.
The patient usually visits a doctor with the aforementioned symptoms. The physical examination may confirm the painlessly enlarged lymph nodes (typically groin, neck, armpits), enlarged liver and enlarged spleen. It is necessary to evaluate the blood count (from a sample of venous blood), where we usually find a high number of white blood cells and lack of red blood cells and platelets. Modern laboratories can easily detect the presence of immature forms of white blood cells called blastic cells. In some types for leukemia there may be even confirmed a specific typical genetic mutation in the tumor cells.
When there are enlarged lymph nodes of an unknown origin, it is advisable to choose an accessible lymph node, remove it surgically and send it to histological examination.
Leukemia is a unique form of cancer. Classic cancer is based on a primary tumor lesion of a body part or an organ (e.g. lung cancer, breast cancer, etc.) and the primary therapeutic opting is surgical removal of the tumor mass. Blood cancers have no clear primary source and the tumor cells are more or less spread throughout the body. Therefore, the primary treatment can not be surgical. Therefore, the basic method is chemotherapy, which is sometimes combined with radiotherapy (for example brain radiotherapy).
In some forms of leukemia, bone marrow transplantation is performed. It is a risky procedure that, simply put, consists of killing the cancer cells and the whole bone marrow by using a powerful chemotherapy and radiation. Subsequently, the patient is given a healthy bone marrow of a donor. The healthy cells of the donor's bone marrow spread throughout the body and inhabit the bone marrow destroyed by previous treatment. The process of transplantation severely weakens the immune system for a time period.
When the curative therapy is not indicated, the patient may be treated symptomatically. In such case, we do not try to cure the leukemia and we only treat its symptoms. The lack of red blood cells can be solved by transfusions, lack of white blood cells by prevention and cautious proper treatment of any infection and lack of platelets by special platelet transfusions.
In the end, let's say some specific attributes of the most common and clinically important leukemias. More detailed information can be found in related texts.
- Acute myeloid leukemia (AML) – infrequent, adults, swollen lips, rapid progression, poor prognosis
- Chronic myeloid leukemia (CML) – adults, the Philadelphia chromosome, slower progression, blastic twist, imatinib