Definition: Defining the Meaning of Leukemia
Leukemia (American English) or leukaemia (British English) is a group of cancers that usually begins in the bone marrow and results in high numbers of abnormal white blood cells. These white blood cells are not fully developed and are called blasts or leukemia cells. Symptoms may include bleeding and bruising problems, feeling very tired, fever and an increased risk of infections. These symptoms occur due to a lack of normal blood cells. Diagnosis is typically by blood tests or bone marrow biopsy.
Leukemia is a form of cancer and like other forms of cancer it begins in cells which make up blood and other kinds of tissues. The body usually produces cells that grow and divide as needed, which are then replaced as new cells are created. Occasionally the process of cell creation goes wrong and new cells are created when they are not needed, while old cells do not die when they are supposed to.
A person's blood cells are formed in their bone marrow, which is a soft material in the center of the majority of their bones. Blood cells that have yet to mature are referred to as, 'Stem Cells,' and, 'Blasts.' The majority of a person's blood cells mature in their bone marrow before moving into blood vessels. Blood that flows through a person's blood vessels and heart is referred to as, 'Peripheral Blood.' Bone marrow produces various types of blood cells and each type of blood cell has a specific function.
The bone marrow in persons with Leukemia produces abnormal white blood cells referred to as, 'Leukemia Cells.' From first appearance, these cells seem to function fairly well. Over time Leukemia cells may begin to outnumber other cells such as red blood cells, white blood cells, and platelets, making it difficult for blood to function properly.
Types of Leukemia
Leukemia is referred to as either Chronic, meaning that it worsens slowly, or Acute, meaning that it worsens quickly.
- Chronic Leukemia: Persons with Chronic Leukemia may not experience any symptoms in the early part of this disease. Over time, the disease worsens, causing symptoms as the number of Leukemia Cells in their blood continues to rise.
- Acute Leukemia: Persons with Acute Leukemia have blood cells that are very abnormal, and are unable to continue carrying out their usual work routine. These blood cells increase rapidly and the disease worsens at a quick rate.
Leukemia is also grouped according to the white blood cells that are affected. Leukemia may begin in either Lymphoid cells, or in Myeloid cells. Leukemia affecting Lymphoid cells is referred to as, 'Lymphocytic Leukemia.' Leukemia affecting Myeloid cells is referred to as, 'Myelogenous Leukemia.'
The four common types of Leukemia include:
- Chronic Lymphocytic Leukemia (Chronic Lymphoblastic Leukemia, 'CLL'): There are approximately seven-thousand new cases of CLL each year, often in persons over the age of fifty-five. CLL very rarely affects children.
- Chronic Myeloid Leukemia (Chronic Myelogenous Leukemia, 'CML'): There are approximately four-thousand four hundred new cases of CML every year, affecting largely adults.
- Acute Lymphocytic Leukemia (Acute Lymphoblastic Leukemia, 'ALL'): There are approximately three-thousand eight hundred new cases of ALL each year. ALL affects adults, but is also the most common form of Leukemia found in children.
- Acute Myeloid Leukemia (Acute Myelogenous Leukemia, 'AML'): There are approximately ten-thousand six hundred new cases of AML every year involving both children and adults.
Risks for Leukemia
The causes of Leukemia are unknown to medical science at this time. Some people are at greater risk of developing Leukemia than others. Research has shown that the following risk factors increase the risk of developing Leukemia.
- Exposure to High Levels of Radiation: Persons who have been exposed to very high levels of radiation are more likely to develop Leukemia than others. The levels of radiation considered to be,' very high,' have been caused by things such as atomic bomb explosions during World War II and exposure to Nuclear Power Plant accidents. Medical treatment using radiation may be another source of radiation exposure. Diagnostic radiation levels use lower levels of radiation, and such use is not linked to Leukemia.
- Exposure to Certain Chemicals: Exposure to either Benzene in the workplace, or Formaldehyde in persons who work in the chemical industry, may increase the risk of developing Leukemia.
- Chemotherapy: Persons who are treated with Chemotherapy drugs sometimes develop Leukemia at a later time. Drugs containing Alkylating agents are associated with development of Leukemia in persons many years later.
- Genetic Diseases: Downs Syndrome and other forms of genetic diseases caused by chromosomes have the potential to increase a person's risk for developing Leukemia.
- Human T-Cell Leukemia Virus-I (HTLV-I): The HTLV-I virus causes a rare form of Chronic Lymphocytic Leukemia referred to as, 'Human T-Cell Leukemia.' While this is viral, it is not contagious.
- Myelodysplastic Syndrome: Myelodysplastic Syndrome is a blood disease that increases the risk of developing Acute Myeloid Leukemia.
Studies performed in the past suggested that exposure to electromagnetic fields, such as the kind produced by electrical appliances and power lines, may be a risk factor for leukemia. Recent studies have shown the evidence related to a connection between electromagnetic fields and a risk for Leukemia are weak.
Symptoms of Leukemia
Leukemia cells travel through a person's body; depending on the number of these cells, as well as where they collect; person's with Leukemia can experience different symptoms. The symptoms of Leukemia can include frequent infections, fevers, night sweats, weakness, tiredness, and headaches. Other symptoms include painful joints or bones, weight loss, swollen lymph nodes - commonly in the armpit or neck, a swollen spleen, and bruising or bleeding easily.
Other things can cause these symptoms. People who are experiencing them need to understand that these symptoms are not a sure sign of Leukemia. A doctor can diagnose and treat these symptoms. Persons who have Chronic Leukemia often do not display any symptoms during the early stages; it may take some time before symptoms do appear. Many times a doctor will discover Chronic Leukemia while performing a routine checkup on the person. With Chronic Leukemia, the person's symptoms are usually mild at first; worsening over time.
Persons with Acute Leukemia experience symptoms that both appear and worsen suddenly. Symptoms that persons with Acute Leukemia may experience include confusion, vomiting, seizures, and loss of muscle control. Leukemia cells have the potential to collect in a man's testicles, causing swelling. Some persons with Acute Leukemia develop sores on their skin, or in their eyes, and experience affects to their kidneys, digestive tracts, lungs, and additional parts of their body.
If a doctor suspects that a person has Leukemia, they will likely perform a physical examination, ask them about both their personal and family history, and order lab tests that include blood testing. There are a number of tests and exams that the doctor may order.
- Physical Exam: During the physical examination, the doctor will look for swollen lymph nodes, as well as swelling of the person's liver and spleen.
- Blood Testing: Blood testing examines the level of white blood cells in the person's system; Leukemia causes a very high level of white blood cells. Testing also looks for the levels of hemoglobin and platelets in the person's bloodstream because Leukemia causes low levels of these. Blood testing checks for signs that Leukemia may have affected the person's kidneys or liver as well.
- Biopsy: A Biopsy involves the removal of a small amount of the person's bone marrow, usually from either their hipbone or another large bone. The sample of bone marrow is then examined by a Pathologist under a microscope to look for cancer cells. A biopsy will tell a doctor with certainty if Leukemia cells are present in the person's bone marrow. There are a couple of ways in which a doctor can get a bone marrow sample, and some patients may have both procedures performed under a local anesthesia. The first is called, 'Bone Marrow Aspiration,' and involves the use of a needle to obtain a bone marrow sample. The second is referred to as a, 'Bone Marrow Biopsy,' and involves the use of a thicker needle.
- Chest X-ray: A Chest X-ray may reveal signs of disease within the person's chest.
- Cytogenetics: Cytogenetics involves a laboratory examination of the chromosomes within cells taken from samples of the person's peripheral blood, lymph nodes or bone marrow.
- Spinal Tap: During a Spinal Tap procedure, a doctor removes a sample of the person's Cerebrospinal Fluid; which is a fluid that fills the spaces surrounding the spinal cord and brain. A doctor does this using a thin, long needle, and the procedure takes approximately thirty minutes to perform. The person is given a local anesthesia for the procedure. Afterward, they must lie flat for several hours to prevent a headache. A laboratory examines the Cerebrospinal fluid for Leukemia cells and additional signs of problems.
Treatment of Leukemia
A doctor may refer a person who has been diagnosed with Leukemia to a specialist who treats Leukemia specifically. Specialists include Medical Oncologists, Hematologists, and Radiation Oncologists. Children diagnosed with Leukemia may be referred to Pediatric Hematologists, or Pediatric Oncologists. Persons diagnosed with Leukemia should seek treatment at a medical center where doctors are present who are experienced in treating it whenever possible.
A second opinion is sometimes helpful, and some insurance companies require it. Other insurance companies may cover a second opinion of the person's doctor requests one. The Cancer Information Center, available at: 1-800-4-CANCER, can provide information to persons who call them regarding treatment centers in their area. State and local medical societies, hospitals, and medical schools may be able to tell people the names of specialists in their area. The American Board of Medical Specialties (ABMS) maintains a list of doctors' names, education, and specialties; the list is available at the public library.
Everyone who is diagnosed with Leukemia is an individual, and both the doctor and the person work together to create a treatment plan that suits the person's needs. Treatment for the person depends on various factors such as the type of Leukemia the person has, their age, the presence of Leukemia cells in the person's Cerebrospinal fluid or not, and whether or not they have been treated for Leukemia before. Certain features of the Leukemia cells may have bearing on the kind of treatment the person receives, as well as the person's general health and the symptoms they are experiencing.
Depending on the different factors involved, the person may receive Biological Therapy, Chemotherapy, Bone Marrow Transplantation, or Radiation Therapy. If their spleen is enlarged the doctor may remove it through a surgical procedure. Sometimes, people receive combinations of treatments.
Persons with Acute Leukemia require prompt treatment; the goal of everyone involved being a remission of the Leukemia. If this is achieved and signs and symptoms disappear - additional therapy can be administered to prevent a relapse. A number of persons with Acute Leukemia are able to be cured.
Persons with Chronic Leukemia who do not present symptoms might not require immediate treatment. A doctor might suggest watching and waiting for some persons who have Chronic Lymphocytic Leukemia, for example. Treatment would begin if the person began showing symptoms that worsen. Treatment for Chronic Leukemia can often be approached as needed to control the disease and its symptoms. Unfortunately; Chronic Leukemia can rarely be cured - it can be controlled through maintenance therapies to keep it in remission.
Additional treatments persons with Leukemia may receive may include treatment for pain and additional symptoms of cancer. Treatment to help with the side-effects of therapy may be included, as well as treatment to help ease emotional issues. These forms of treatment are referred to as, 'Symptom Management,' 'Supportive Care,' or, 'Palliative Care.'
The majority of persons with Leukemia receive Chemotherapy, a form of treatment that uses drugs to kill leukemia cells. Chemotherapy may involve the use of one or more drugs. The treatment may be administered in different ways, one of which is through oral medications. Persons with Leukemia may also receive Chemotherapy intravenously.
- Intravenous Chemotherapy: Intravenous administration of Chemotherapy might involve the use of a, 'Catheter,' or thin and flexible tube which is placed into the person's vein, sometimes in the person's chest. People who need a number of treatments may have a catheter put in that stays in place for a period of time. A health care provider injects medications through the catheter into the person's vein, avoiding the need for multiple injections that may cause the person unnecessary discomfort, or injure their skin and veins.
- Cerebrospinal Chemotherapy: If a pathologist finds Leukemia cells in the person's Cerebrospinal fluid, a doctor may order, 'Intrathecal Chemotherapy.' A doctor injects chemotherapy drugs directly into the person's cerebrospinal fluid in one of two ways. A doctor may inject the drugs into the lower part of the person's spinal column. Children, and some adults with Leukemia, receive Intrathecal Chemotherapy through a catheter known as an, 'Ommaya Reservoir.' The person's doctor inserts a catheter under their scalp and injects the chemotherapy drugs through the catheter, avoiding injection into the person's spine.
Chemotherapy is administered in cycles that involve a period of treatment followed by a period of recovery. Some people receive chemotherapy treatments on an outpatient basis through a doctor's office, at a hospital, or even in their home. For others, a hospital stay may be needed.
Some persons with Chronic Myeloid Leukemia are receiving a new form of treatment referred to as, 'Targeted Therapy.' Targeted Therapy blocks production of Leukemia cells while avoiding harm to other cells in the person's body. 'Gleevec,' also referred to as, 'STI-571,' is the first Targeted Therapy that has been approved for persons with Chronic Myeloid Leukemia.
Biological Therapy: Biological Therapy involves the use of a person's own body and its natural defenses to fight against Leukemia. Biological therapy is administered intravenously, and for some persons with Chronic Lymphocytic Leukemia, it helps their immune system to kill Leukemia cells in the blood and bone marrow. Biological therapy uses a monoclonal antibody called, 'Interferon.'
Radiation Therapy or, 'Radiotherapy': Radiation therapy involves the use of high energy rays to kill Leukemia cells. A large machine directs radiation at areas in the person's body where Leukemia cells have collected, such as in their spleen, brain, or other places. Some persons receive Radiation therapy directed towards their entire body, usually prior to being given a bone marrow transplant. Radiation therapy is usually administered at a clinic or a hospital.
Stem cell transplantation
Persons with Leukemia may have a stem cell transplant, allowing them to be treated with high doses of radiation, drugs, or both. The higher doses of radiation and drugs can destroy Leukemia and regular blood cells in the person's bone marrow. At a later time, the person receives healthy stem cells through a tube in a large vein in either their chest or neck area, from which new blood cells develop.
There are a number of types of Stem Cell transplantations. Stem cells can be received from either the person, or from a donor.
- Bone Marrow Transplantation: Bone Marrow Transplantation involves stem cells that are transferred from bone marrow.
- Peripheral Stem Cell Transplantation: Peripheral Stem Cell Transplantation involves stem cells that are transplanted from peripheral blood.
- Umbilical Cord Blood Transplantation: For children who have no donor, a doctor may use stem cells from umbilical cord blood. At times, umbilical cord blood is frozen with the intention of using it later.
- Autologous Stem Cell Transplantation: Autologous Stem Cell Transplantation involves using the person's own stem cells that have been removed, and potentially treated, to kill any Leukemia cells. The person's stem cells are frozen and stored. Once the person has received chemotherapy or radiation therapy, their stored stem cells are thawed and returned to them.
- Allogeneic Stem Cell Transplantation: Allogeneic Stem Cell Transplantation involves the use of healthy stem cells that have been donated from the person's parent, brother, or sister. On occasion, these stem cells may come from an unrelated donor. In all cases, a doctor will use blood tests to ensure that the donor's cells are compatible with the patient's cells.
- Syngeneic Stem Cell Transplantation: Syngeneic Stem Cell Transplantation involves using stem cells from the person's healthy identical twin. Persons who have received a stem cell transplant commonly stay in the hospital for several weeks. Health care providers work to prevent the person from developing an infection until the stem cells they have received start producing a sufficient quantity of white blood cells.
Side-Effects of Leukemia Treatment
Treatment for Leukemia can damage healthy tissues and cells in persons with the disease, producing undesired side-effects. The side-effects a person will experience depend on a number of different factors that are based on the individual. The side-effects a person experiences may change from one treatment session to the next as well.
Side-Effects of Chemotherapy
Chemotherapy drugs produce different side-effects, which vary upon their dosage too. Generally, chemotherapy drugs can have side-effects such as making the person feel weak and tired, causing them to bruise or bleed more easily, and hair loss. When the person's hair does grow back it may be somewhat different in texture and color. Chemotherapy can cause lip and mouth sores, diarrhea, vomiting, and poor appetite; fortunately, many of these particular symptoms can be controlled with medications.
Some forms of chemotherapy drugs may affect the person's fertility. Women may experience symptoms of menopause, irregular menstrual periods, or stop having periods altogether. Men may stop producing sperm, perhaps permanently. Children who are treated for Leukemia seem to regain their fertility as they mature, although depending on their age, the drugs used, and the dosages; some children may remain infertile. Targeted therapy affects only Leukemia cells, is used for Chronic Myeloid Leukemia, and causes fewer side-effects.
Side-Effects of Biological Therapy
Persons who receive Biological Therapy experience different side-effects depending on the substances used. They may experience flu-like symptoms, and swelling and rashes around the site where the treatment was injected are common. Health care providers watch persons who receive Biological Therapy for signs of Anemia and other issues.
Side-Effects of Radiation Therapy
Radiation Therapy leaves people who receive it feeling tired as the treatment process continues. Doctors advise persons receiving Radiation therapy to stay as active as they can, but resting is important as well. Persons who receive this form of treatment commonly experience red, dry and tender skin in the area where they have received the treatment.
Side-Effects of Stem Cell Transplantation
Persons who have received Stem Cell Transplants are at greater risk for bleeding and infection, as well as other side-effects, because of the large doses of radiation and chemotherapy they have received. Graft-Versus-Host Disease (GVHD) can develop in people who have received stem cells from a donor's bone marrow. GVHD involves a reaction where the donated stem cells react against the person's tissues, commonly affecting the person's skin, liver, or digestive tract. The affects of GVHD can range from mild to severe and may happen at any time after a transplant - even years afterward. Steroids and other medications may help with GVHD.
Patients who have stem cell transplantation face an increased risk of infection, bleeding, and other side effects because of the large doses of chemotherapy and radiation they receive. In addition, graft-versus-host disease (GVHD) may occur in patients who receive stem cells from a donor's bone marrow. In GVHD, the donated stem cells react against the patient's tissues. Most often, the liver, skin, or digestive tract is affected. GVHD can be mild or very severe. It can occur any time after the transplant, even years later. Steroids or other drugs may help.
Facts: Leukemia Research
Significant research into the causes, prevalence, diagnosis, treatment, and prognosis of leukemia is being performed. Hundreds of clinical trials are being planned or conducted at any given time. Studies may focus on effective means of treatment, better ways of treating the disease, improving the quality of life for patients, or appropriate care in remission or after cures. Treatment through gene therapy is currently being pursued. One such approach used genetically modified T cells to attack cancer cells. In 2011, a year after treatment, two of the three patients with advanced chronic lymphocytic leukemia were reported to be cancer-free and in 2013, three of five subjects who had acute lymphocytic leukemia were reported to be in remission for five months to two years. Identifying stem cells that cause different types of leukaemia is also being researched.
Statistics: U.S. Leukemia
- Approximately every 3 minutes one person in the United States (US) is diagnosed with a blood cancer.
- Prevalence of this cancer: In 2011, there were an estimated 302,800 people living with leukemia in the United States.
- Leukemia, lymphoma and myeloma are expected to cause the deaths of an estimated 55,350 people in the US in 2014.
- An estimated combined total of 156,420 people in the US are expected to be diagnosed with leukemia, lymphoma or myeloma in 2014.
- These diseases are expected to account for 9.4 percent of the deaths from cancer in 2014, based on the estimated total of 585,720 cancer deaths.
- New cases of leukemia, lymphoma and myeloma are expected to account for 9.4 percent of the estimated 1,665,540 new cancer cases diagnosed in the US in 2014.
- Approximately every 10 minutes, someone in the US dies from a blood cancer. This statistic represents nearly 152 people each day or more than six people every hour.
- Lifetime Risk of Developing Cancer: Approximately 1.4 percent of men and women will be diagnosed with leukemia at some point during their lifetime, based on 2009-2011 data.
- Number of New Cases and Deaths per 100,000: The number of new cases of leukemia was 13.0 per 100,000 men and women per year. The number of deaths was 7.0 per 100,000 men and women per year. These rates are age-adjusted and based on 2007-2011 cases and deaths.