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Leukemia: The Blood Cancer

by — 2014-11-19 in Cancer
According to the Leukemia and Lymphoma Society, more than 52,000 people will be diagnosed with leukemia during 2014 and almost half of them are expected to die from the disease. Let´s take a look at its causes, how it is diagnosed and its treatment.

Cancer is the consequence of an alteration at the level of the cellular DNA. The alteration can be hereditary or can be caused for example by UV rays or other environmental factor. These alterations, also known as mutations, are specifically located in genes that control the proliferative capacity of the cells, making them immortal. Mutated cells can proliferate without control and so, they start forming tumors, or masses of abnormal cells, which cause normal cells to die and tissue damage, among other complications.

Abnormal cells in the blood

Blood cancer is a bit different though. 

This type of cancer does not characterize for the development of tumors but more for an increase in the number of abnormal blood cells traveling through the circulatory system and a decrease in the number of normal blood cells.
 
Blood cancers have their origin in the bone marrow, which is the spongy tissue located in the hollow centres of some bones, where blood cells are produced.

A normal bone marrow is full of stem cells that grow and reach a mature state while living there. When they reach maturity, these cells are released into the bloodstream as red blood cells, white blood cells and platelets. Red blood cells are in charge of transporting oxygen from the lungs to every single organ in our body; white blood cells are part of the immune system and help it battle against infections; platelets participate in the formations of clots during the coagulation cascade.

In patients with blood cancer, abnormal cells, which usually stay in an immature state, are released into the bloodstream.

These cells do not function as they normally do, putting at risk the life of the patient, since the oxygen transport, the immune system and the coagulation system get compromised. These cells also tend to accumulate in certain organs, because they are circulating in abnormally high numbers through the bloodstream. Accumulation of the cells also alters the function of the organs where they get stuck, which are usually the spleen and the liver. 

Types of blood cancer

There are several forms of blood cancers, depending on the type of blood cell that is affected. Myeloma is characterized by the proliferation of abnormal plasma cells, which are the ones in charge of producing antibodies that target and flag disease causing agents so that the immune system can identify them. 

Myeloma cells affect the production of these antibodies, therefore leaving the patient without weapons to fight against infections.

Lymphoma affects the lymphatic system. This system is the one in charge of draining excess fluids from the body and also participates in the production and maturation of immune cells.

Lymphoma develops as a consequence of the production of abnormal white blood cells, which are collected in the lymph nodes and impair the immune system response. 
 
Lymphomas are divided into Hodgkin and non-Hodgkin lymphoma and in general, lymphoma accounts for almost half of the blood cancer cases that occur per year.

See Also: Hodgkin's Vs Non-Hodgkin's Lymphoma: Differences

Finally, leukemia is also a type of blood cancer, which differs from myeloma and lymphoma in the types of bone marrow cells that are affected and the presentation of the disease, although most of the times, the symptoms may be similar to each other.  

Leukemia: Types, Diagnosis And Treatment

Leukemia usually presents in an acute or a chronic form and affects both adults and children. The acute form of leukemia occurs suddenly and it is usually diagnosed by the presence of immature white blood cells in the bloodstream of the patient. Chronic leukemia develops more slowly; it takes weeks or even months to progress, so patients are usually under vigilance to evaluate the progression of the disease before taking any treatment. In the case of the acute form, this one usually requires immediate treatment, since the production of immature cells is very intense.

Myelogenous and lymphocytic leukemia  

Leukemia is also classified in myelogenous when the affected cells are the precursors of the three blood cells types: white blood cells, red blood cells and platelets; and in lymphocytic, when the abnormal cells are the precursors of white blood cells, also known as lymphocytes.

The main feature of lymphocytic leukemia is the overproduction of white blood cells in the bone marrow.

Since this last one starts filling up with immature lymphocytes, they have to be released into the bloodstream before they finish their maturation process. Immature lymphocytes are not able to fight infections and because the bone marrow is busy producing them, it stops producing red blood cells and platelets.

Myelogenous leukemia, on the other hand, does not characterizes by the overproduction of immature cells, but of abnormal mature cells that are also released into the bloodstream, does not function as they should and affect other tissues as well.

Acute lymphocytic leukemia is the most common type of leukemia that affects children, while acute myelogenous leukemia is more common in adults.

Symptoms, diagnosis and treatment of leukemia  

Because all blood cells are affected by leukemia, the patient usually presents a mixed symptomatology, which is the result of the lack of these cells.

For example, symptoms of leukemia in children and adults can signalize in fever, bruises, bone pain, painless lumps in the neck, underarm, stomach or groin, weakness and paleness, loss of appetite, anemia and low counts of blood cells.

The diagnosis of any type of leukemia relies on the number of blood cells present in the patient. When cell blood counts for normal cells are decreased, the analyst also takes a small sample of circulating blood from the patient to look under the microscope. This microscopic analysis will allow the detection of immature cells, since their morphology is different to the morphology of the mature ones. A bone marrow biopsy may also be necessary, depending on the results shown in previous tests.

Depending on the type of leukemia and the progression of the disease, treatment will be based on chemotherapy and radiotherapy.

See Also: Interferon Treatment For Leukemia

These treatments are aimed to destroy the abnormal cells in the patients’ body. As a last resource, a bone marrow transplant will be performed in order to replace the defective bone marrow from the patient, which produces abnormal cells, with a normal bone marrow from a healthy donor.

The prognosis of the disease depends on several factors, including the age of onset of leukemia, the gender of the patient, if it is acute or chronic and the type of cells that are affected, the presence of a different disease, such as Down syndrome, the causing agent, which can be a genetic mutation, and if the cells have spread to the brain or not. 

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