About Acute lymphocytic leukemia
Acute lymphocytic leukemia (ALL) is one among types of leukemia which begin when immature white blood cells named lymphocytes start to grow out of control. Acute lymphocytic leukemia is sometimes called acute lymphoblastic leukemia. The term “Acute’’ simply means leukemia can progress quickly, and without treatment it is likely to be fatal within a few months although if treated in time, most cases of ALL respond to treatment very well. To understand leukemia, it is important for one to know blood first.
Blood is a fluid flowing in our bodies and it is the one that usually conveys nutrients and oxygen. In the body blood is carried in specified tubes known as vessels (veins and arteries). Blood is pumped around the body by a muscular organ called heart. Blood is made up of blood cells carried in a clear fluid called plasma. Blood cells are mainly of three types, red blood cells, white blood cells and platelets.
• Red blood cells. These carry oxygen around the body
• White blood cells. These are responsible for fighting infections
• Platelets. These help in blood clotting.
All these blood cell types have a limited life span, hence they are continuously replaced. Most are made in the bone marrow, which is the spongy part in the center of the bones such as the skull, ribs, hip bones, shoulder blades and backbones (vertebrae). Since leukemia is a blood cancer that mainly involves white blood cells, it is important to have a bit more knowledge on white blood cells.
Types of white blood cells
• Lymphocytes. These are responsible for fighting infections and they develop from stem cells known as lymphoblast. Lymphocytes are the cells that mainly make up lymphoid tissue, which are major part of the immune system. The two main types of lymphocytes are;
• B- Cell lymphocytes. These cells make antibodies that fight germs and other infections. These are also called B-Cells.
• T-Cell lymphocytes. These are responsible for destroying germs and also they trigger B-cell lymphocytes to produce antibodies
• Granulocytes. These are mature cells that are responsible for fighting infections. These cells develop from myeloblasts. They are known as granulocytes because they have granules that show up as spots under the microscope. Types of white blood cells known as granulocytes include; neutrophils, eosinophils and basophils. These three differ in color and size of granule.
• Monocytes. These develop from blood-forming monoblasts in the bone marrow. After sometime in the blood stream, monocytes will enter body tissues to become macrophages. Macrophages destroy germs but also they help lymphocytes recognize germs.
Leukemia is a term used to describe blood cancer. Leukemia originates from the term leucocytes which mean white blood cells. In leukemia patients, white blood cells grow abnormally and multiply in such a way that they crowd the bone marrow. This can reduce the bone marrow’s ability to produce normal levels of other blood cells, which will affect the way the rest of the body works.
The bone marrow contains stem cells. These are unspecialized blood cells that first develop into immature cells known as blast cells. Normally, the blast cells then become mature red or white blood cells or platelets and carry out their set functions but if the blasts fail to mature properly or if they are too many in the blood, it may result to leukemia. There are two types of stem cells;
• Myeloid stem cells. This develop into myeloblast cells that further develop into red blood cells, platelets and most types of white blood cells.
• Lymphoid stem cells. This develop into lymphoblast cells which then becomes lymphocytes which are type of white blood cells.
Following failure to mature properly into normal blood cells, myeloblast cells will result to development of type of leukemia known as myeloid leukemia while lymphoblast cells will result into lymphoblastic leukemia.
As leukemia progresses, the bone marrow produces more abnormal blood cells and fewer normal blood cells. Abnormal blood cells spill out into the blood stream and build up in the blood. This may result into spreading to other parts of the body such as lymph nodes, lungs, liver, spleen and kidneys.
In this section the discussion will base on acute lymphocytic leukemia, which is one of the main two type`s lymphocytic (lymphoblastic) leukemia. Lymphocytic leukemia is divided into acute and chronic lymphocytic leukemia. Acute means the disease progress quickly and can be fatal within few months if not treated while chronic is the vice versa. Both types develop from immature lymphocytes.
In addition to lymphocytic leukemia, another type of cancer that start in lymphocytes is known as lymphoma (Hodgkin or Non-Hodgkin lymphomas). The main difference between these types of cancer is that leukemia, mainly affects the bone marrow and the blood while Lymphomas mainly affect the lymph nodes although sometimes it may involve the bone marrow.
Sometimes during diagnosis cancer cells can be found in both bone marrow and lymph nodes. In cases like these it becomes a bit trick to tell if cancer is leukemia or lymphoma but to differentiate the two, doctors consider number of lymphocytes in the bone marrow and lymph nodes. If bone marrow and blood has large number of those cells (lymphocytosis), then it is leukemia but if nodes have more cells it is lymphoma (small lymphocytic lymphoma).
Risk factors of acute lymphocytic leukemia
When dealing with cancer, a risk factor is anything that increase a person`s chance of developing cancer. Risk factor only influence development of cancer but does not directly cause cancer. Sometimes people with different risk factors do not develop the disease while those with no risk factors do develop the disease. Knowing risk factors will help you live your life making some better healthy choices to reduce the probability of developing the disease. The risk factors for acute lymphocytic leukemia include the following;
• Viral infections. Epstein-Barr virus infections is highly linked to some form of acute lymphocytic leukemia. Although it is not common in Africa including Tanzania, human T-cell leukemia virus-1 (HTLV-1) infection is also linked to development of acute lymphocytic leukemia.
• Radiation exposures. Exposure to high levels of radiation increases chance for someone to develop leukemia. This includes long term survivors of atomic bombs and victims of radiation accidents (high energy radiation) such as those working with radiations.
• Genetic conditions. There are some genetic conditions that are highly linked to development of leukemia. These conditions include, Down syndrome, neurofibromatosis, Klinefelter syndrome, ataxia-telangiectasia, li-fraumen syndrome and fanconi anemia.
• Chemical exposure. Exposure to some chemicals such as benzene which is used in various places such as oil refining plants, rubber processing industries and shoe manufacturing industries, may increase the chance for developing leukemia at some point in life.
• Cigarette smoking. Cigarette smoke also contains benzene which is one of the chemicals linked to leukemia.
• Gender. Statistics shows that, number of men affected by ALL is slightly higher compared to that of women.
Prevention of acute lymphocytic leukemia
To prevent something, you first need to know what causes it.
But since the specific cause of acute lymphocytic leukemia is still unknown, there is no way of completely preventing the development of this cancer.
In addition to that, the risk of developing many other types of cancer can be reduced with some lifestyle changes. But since there are few known risk factors for this disease and most of them cannot be changed, preventing this disease becomes nearly impossible.
However, one may lower the risk by avoiding or quitting smoking and for those working with chemicals in industries should use protective gears while working with those chemicals.
Early detection and screening of acute lymphocytic leukemia
When it comes to cancer, early detection normally provide better treatment outcome. When acute lymphocytic leukemia (ALL) is found early, chances for better treatment outcome are very high. For most cancers, early detection has been greatly contributed by the presence of screening processes.
Screening is the process of running some tests to someone with no symptoms of the disease with the intention of determining presence or absence of the disease. Unfortunately, currently there are no widely recommended screening tests for ALL. The best way for early detection is reporting to the hospital as soon as you start experiencing any possible signs or symptoms of this disease.
For those known to have higher risk of ALL such as those with inherited genetic disorder like down`s syndrome and klinefelters syndrome, it is recommended that they have appropriate regular medical checkups.
Signs and symptoms of acute lymphocytic leukemia
Sometimes there may be no any signs or symptoms but people with ALL may experience the following;
• Feeling tired
• Feeling weak
• Easily bruising and bleeding
• Persistent infections
• Shortness of breath
• Enlarged liver and spleen
• Unexpected weight loss
• Enlarged lymph nodes
• Nausea and vomiting
Sometimes these symptoms may be a result of another medical condition, but if someone experience any of those symptoms he/she is advised to go to the hospital immediately.
Diagnosis of acute lymphocytic leukemia
Following suspicions of acute lymphocytic leukemia, various tests are used to verify the suspicions, learn if the disease has spread to other organs of the body and some tests will help to determine prognosis of the disease. When running those diagnostic tests, the doctor will consider some of the factors including;
• Results of the previous tests
• The general health condition
• Type of cancer suspected
The following are some of the diagnostic tests for acute lymphocytic leukemia (ALL) although not everyone will need to go through all those tests during diagnosis.
• Medical history and physical examination. The doctor will review patient`s history for risk factors but also do some physical examinations to check if there is any enlarged lymph nodes (lymphadenopathy) and abdominal swelling which can be a result of enlarged liver (hepatomegaly) and spleen (spleenomegaly).
• Blood tests. Blood samples will be taken and checked in the laboratory for full blood count (FBC). The results will reveal whether the levels of blood cells are normal or not. Blood sample may also be used to find if the blood cells are normal or abnormal (leukemia cells).
• Bone marrow tests. If the blood test shows abnormalities in the number or appearance of the white blood cells, the doctor may take some bone marrow sample to check for signs of leukemia. There are two main procedures used in taking bone marrow samples for testing;
• Bone marrow aspiration. This involves the removal of a fluid sample by using a needle (fluid part of bone marrow).
• Bone marrow biopsy. This involve the removal of a small amount of solid tissue using a needle.
If the results from blood tests suggest presence of leukemia, bone marrow tests are advised to be done at the hospital where treatment will be given so as not to do these tests twice.
• Immunophenotyping. This test is also known as flow cytometry. It uses a machine called flow cytometer to check for presence of certain markers or signals (antigens) on cell surfaces. The tests help to identify ALL from healthy blood cells and from other types of leukemia that also involve lymphocytes. From this test the doctor can also determine the subtype of ALL and type of lymphocyte cell (B-cell or T-cell) from which the leukemia has originated.
• Genetic tests. These include cytogenetic and molecular tests. These tests are specific for studying genetic makeup of cancer cells which is different to that of normal cells as cancer cells have some faults to their genetic makeup.
• Lumbar puncture. Lumber puncture is a procedure in which a doctor uses a needle to take a sample of cerebral spinal fluid (CSF) and examine to check for presence of cancer cells. ALL tends to spread to the CSF, which is the fluid that flows around the brain and spinal cord, so by testing the CSF sample the doctor will be able to determine if the disease has spreads to the fluid or not.
• Imaging tests. Imaging tests like CT scan, MRI scan, chest X-ray and PET scan are used to determine if the disease has spread to other parts of the body such as lymph nodes, liver and spleen.
Classification of acute lymphocytic leukemia
There are various systems used for classification of blood cancers. When dealing with acute
Lymphocytic leukemia, doctors prefer to classify the disease by using immunophenotyping results.
Classification of ALL based on immunophenotype
Classification of ALL by using immunophenotype depends on maturity of cancer cells. The classification of this leukemia has been grouped into two groups (subtypes) depending on the cells from which the disease has originated. The subtypes include;
Those of B-cell lymphocytes.
• Early pre B-cell acute lymphocytic leukemia
• Common B-cell acute lymphocytic leukemia
• Pre B-cell acute lymphocytic leukemia
• Matured B-cell acute lymphocytic leukemia (Burkitt leukemia)
Those of T-cell lymphocytes
• Pre T-cell acute lymphocytic leukemia
• Mature T-cell acute lymphocytic leukemia
Treatment of acute lymphocytic leukemia
Following cancer diagnosis, the doctor will break the news and it is normally not very easy to accept that it is cancer. The doctor will be there to help the patient process the news and to help the patient in taking the next steps.
After the patient receives and processes the news that he/she has cancer, one of the most important steps that will follow is decision making. The doctor will present to the patient (relatives/parents/guardians) with all the possible treatment options and explain what they mean. Then with the help of the doctor, the patient (relatives/parents/guardian) will have to choose which treatment option is good depending on benefits of such option.
Despite all the information given by the doctor, sometimes the patient may still be unsatisfied with what he/she has been told. In such situation, the patient is free and advised to seek a second opinion. Second opinion is the opinion that the patient may seek from another specialist (doctor) regarding his/her health problem and in this case it is cancer. Second opinion may include confirmation of the diagnosis, more clarification on your primary doctor recommendations or even reassurances that all the options have been explored.
In addition to standard care treatment options, sometimes there are those new treatments or drugs or combination of treatments that have not been approved yet to be used as standard care treatments for a particular cancer (disease) but have shown some promising results that they may help. These type of treatments are called clinical trials.
If there are some clinical trials for your case, the doctor may present to the patient or the patient may ask if there are any clinical trials for the particular cancer case. Over the years, have improved treatments and led to better outcomes to people diagnosed with various diseases including cancer. If you have decided to take part in clinical trial, you can also withdraw at any time
Treatment of ALL requires a team of doctors and other health care professionals. This team work together and it is called multidisciplinary team. This team may vary from one from one patient to another depending on the treatment option for a particular case. But generally multidisciplinary team for treatment of ALL includes hematologist, medical oncologist, radiation oncologist and other health care professionals like oncology nurses and palliative care team. Treatment options for ALL include the following;
Chemotherapy is a treatment option that involve the use of drugs to destroy cancer cells or slow its growth. It is given by a specialized doctor known as medical oncologist or hematologist. Chemotherapy is normally given through injection into veins (intravenously) and rarely swallowed as pill or capsule.
A chemotherapy schedule, normally consists of a specific number of cycles that are given over a set period of time. Patients with ALL normally tend to receive several different drugs throughout their treatment.
Side effects of chemotherapy
Side effects of chemotherapy depends on type of drug used, dose given and periodic time by which the drug has been used. Possible side effects of chemotherapy include the following;
• Loss of hair
• Mouth sores
• Nausea and/or vomiting
• Risk of infections
• Easily bruised and bleeding
This is a treatment option that involve injecting the chemotherapy drug directly into the disease site. It is most used to those with ALL cells into their CSF fluid. To these people, normal chemotherapy cannot work as drugs injected intravenously or taken as pill doesn`t reach into the spine so directly injecting the drug into the spine is the option for these cases.
This is the treatment option that involve using high energy x-rays or other radiation particles to destroy cancer cells. It is a treatment option given by a specialized doctor known as radiation oncologist.
Between the two types of radiation therapy, external beam radiation therapy is the one that is used when dealing with ALL. It is used to destroy cancer cells around the brain or spinal column and kill remaining cancer cells in the bone marrow before stem cell transplantation. In addition to killing reaming cancer cells, whole body irradiation (total body irradiation) given before stem cell transplantation helps to weaken body immunity and reduce risk of rejection of transplanted cells.
Side effects of radiation therapy
Side effects of radiation therapy will depend on the site of treatment and dose of radiations given. Possible side effects of radiation therapy include the following;
• Mild skin reactions
• Loss of hair
• Feeling tired
• Upset stomach
• Loose bowel movement
Stem cell transplant
Stem cell transplantation is a treatment option that involve replacing a patient`s bone marrow by highly specialized blood forming cells known as hematopoietic stem cells. Bone marrow that contain cancer cells is destroyed first by using high dose of chemotherapy or radiation therapy, then replaced by healthy stem cells.
This treatment option is sometimes known as bone marrow transplantation. Transplanted cells will mature into healthy bone marrow.
Stem cell transplantation is divided into two types;
• Autologous stem cell transplantation. This type uses stem cells that were previously removed from patient`s blood stream and later are transplanted (rein fused) back into his/her body.
• Allogeneic transplantation. This involve the use of stem cells taken from another person (donor). The donor may be your family member or from a donor registry.
For treatment of ALL, allogeneic stem cell transplantation is normally preferred. Transplantation is normally done in several stages and the entire procedure, including recovery, can take months.
Side effects of stem cell transplantation
Most of the side effects of this treatment option resemble to those of chemotherapy but with this treatment options the side effects may be severe. Those possible side effects of stem cell transplantation include the following;
• Nausea and vomiting
• Hair loss
• Risk of infection
• Easily bruising and bleeding