What Is Leukemia?

Leukemia is a form of blood cancer that starts in your bone marrow, the spongy tissue inside your bones. It occurs when abnormal cells grow too fast and survive too long. Over time, the abnormal cells overtake the normal cells. Symptoms occur as the normal cells fail to perform their tasks, leading to infections and pain.

There are many forms of this disease. Symptoms can progress quickly or slowly, based on the form of leukemia you have. Knowing the type of disease you have is key to choosing the right treatment and getting the best results. While the disease can't truly be cured, you can achieve a state in which symptoms and leukemia cells don't appear for years.

This article describes leukemia types, symptoms, causes, staging, and treatments.

How Does Leukemia Develop and Spread?

Leukemia develops when your bone marrow rapidly produces abnormal white blood cells called leukemia cells. These cells reproduce faster than normal cells and don't die when they should.

As they increase, leukemia cells outnumber normal white blood cells, and the disease may affect the production of red blood cells and platelets. This can make it hard for normal cells to perform their functions like fighting infection or stopping bleeding. It also prevents your bone marrow from making more normal blood cells.

As more leukemia cells crowd your bone marrow, they eventually overwhelm the bone marrow and enter the bloodstream. This allows them to circulate through your body and affect other areas like your lymph nodes or other organs.

Types of Leukemia

There are four main types of leukemia:

• Acute myeloid leukemia (AML): AML is one of the most common forms of leukemia in adults. It is a fast-growing type that develops in myeloid stem cells, which normally mature into white blood cells (other than lymphocytes), red blood cells, or platelets. Subtypes include acute myelocytic leukemia, acute myelogenous leukemia, acute granulocytic leukemia, and acute non-lymphocytic leukemia. The abnormal cells can spread into the blood and other parts of the body.
• Acute lymphocytic leukemia (ALL): Acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia, is the most common form of childhood leukemia. In ALL, your bone marrow produces too many immature lymphocytes (called lymphoblasts). Lymphocytes are a type of white blood cell that fights bacteria and viruses. Immature lymphocytes can't fight infection. As this fast-growing cancer produces too many abnormal lymphocytes, they overwhelm the normal lymphocytes in your bone marrow.
• Chronic myeloid leukemia (CML): Chronic myeloid leukemia (CML), also called chronic myelogenous leukemia, is a slow-moving bone marrow cancer that affects mature myeloid cells. It causes too many myeloid cells to become granulocytes, which normally help fight infection. The cancerous cells are poor at fighting disease. Almost all people with CML have a chromosome abnormality known as the Philadelphia chromosome.
• Chronic lymphocytic leukemia (CLL): Chronic lymphocytic leukemia is a slow-moving cancer that develops in a type of white blood cell called B-lymphocytes or B cells. CLL mostly affects older adults. It is very similar to ALL, though CLL develops much slower and may exist for several years before it causes symptoms.

Leukemia Symptoms

Many leukemia symptoms can resemble other blood disorders or diseases. Symptoms can differ based on the type of leukemia and the age of diagnosis. If any of the following symptoms occur for two weeks or longer without improvement, contact your healthcare provider for an examination.

Early Signs

Many early signs of leukemia may easily be overlooked or attributed to other causes. These signs and symptoms include the following:

• Loss of appetite
• Unexplained weight loss
• Fatigue
• Bruising and bleeding easily
• Chronic nosebleeds
• Headaches
• Heightened sensitivity to hot and cold temperatures
• Bone pain and joint pain
• Dizziness or light-headedness
• Fever, chills
  
• Night sweats
  
• Petechiae (small red bruises under the skin)
• Abdominal discomfort
• Pale skin
• Swollen gums or lymph nodes
• Vomiting
• Aches in your arms, legs, or hips
• Enlarged spleen or liver causing tenderness below your rib cage on your left side
  

As It Spreads

Leukemia symptoms tend to become more frequent and severe over time as more abnormal white blood cells are produced. However, it is hard to identify the disease stage from symptoms alone.

Early symptoms that occur with acute forms of leukemia, like ALL or AML, can begin and intensify suddenly over a matter of days or weeks. They become more severe faster than those that occur with chronic forms of leukemia.

Early symptoms of chronic types of leukemia (CLL or CML) can develop slowly, taking months or years to appear even though the disease is present.

Signs of Leukemia in Kids

While children can experience leukemia symptoms differently, they can have many of the same signs of leukemia that occur in adults. The most common signs of leukemia in kids include the following:

• Bleeding and/or bruising easily
• Petechiae
• Recurrent viral or bacterial infections
• Frequent fevers, runny noses, or coughs
• Bone and joint pain
• Abdominal pain
• Loss of appetite and/or unexplained weight loss
• Dyspnea (difficulty breathing)
• Swollen lymph nodes under the arms or in the chest, groin, or neck
  

What Causes Leukemia?

Leukemia results from gene mutations that lead to the development of leukemia cells in your bone marrow. These cells grow faster and live longer than normal cells. These abnormal cells overwhelm the development of healthy cells, interfering with the functions that they usually support.

While the exact causes of leukemia are unknown, there are several known risk factors for this disease.

Risk Factors for Leukemia

The most prevalent risk factors for leukemia include the following:

• Age 60 or over (for most cancers)
• Age 20 or under (for ALL)
• Certain blood disorders, such as myelodysplastic syndromes
• Exposure to high levels of radiation, benzene, and some chemicals used in the rubber and petroleum industries
• Having had chemotherapy or radiation therapy for a previous cancer
• Smoking
• Family history
• Some congenital (present at birth) syndromes, including Down syndrome, Fanconi's anemia, Bloom syndrome, Louis-Bar syndrome (ataxia-telangiectasia), Diamond Blackfan anemia, and Klinefelter's syndrome
  

How Is Leukemia Diagnosed?

Several steps are involved in confirming a leukemia diagnosis and monitoring disease progression. Your healthcare provider will use one or more of the following tests to determine whether you have leukemia:

Testing

Your healthcare provider will use one or more of the following tests to determine whether you have leukemia:

• Physical exam: A physical exam checks your overall health and looks for signs of leukemia, which can include swelling, bruising, or pale skin. They will also review your report of symptoms, health history, and diseases in your immediate family.
• Complete blood count (CBC): This blood test measures the size, number, and maturity of different blood cells.
• Peripheral smear: This blood test provides more details about the type of white blood cells in your blood. It can show the proportion of immature and mature blood cells. A drop of blood is spread on a microscope slide, dyed, and examined by a lab professional.
• Bone marrow aspiration and biopsy: This procedure involves removing a small sample of bone marrow for evaluation. A needle is inserted into the hip bone, though other sites may be used. A sample of bone marrow is taken and examined in the lab.
• Flow cytometry: Flow cytometry involves coating bone marrow cells or peripheral blood cells to identify the presence of certain surface proteins related to leukemia on these cells.
• Magnetic resonance imaging (MRI): An MRI creates a series of detailed pictures of your body using a magnet, radio waves, and a computer. It may be performed with or without injecting a contrast medium called gadolinium to highlight cancer cells in the images.
• Computed tomography (CT) scan: A CT scan produces a series of detailed X-ray pictures of areas inside your body taken from different angles. A dye may be injected or swallowed to help the radiologist identify tissues or organs in the pictures.
• Positron-emission tomography (PET) scan: A PET scan uses radioactive sugar injected into your blood to show cancer cells.
• X-ray: An X-ray uses a small amount of radiation to take pictures of your bones and other body tissues to show damage.
• Ultrasound: An ultrasound, or sonography, uses high-frequency sound waves and a computer to create images of organs, tissues, and blood vessels. Ultrasound provides a view of the function of internal organs to assess blood flow through various vessels.
• Sentinel node biopsy: A sentinel node biopsy, also called a lymph node biopsy, involves removing a tissue sample from a lymph node so it can be examined under a microscope.
• Spinal tap/lumbar puncture: A spinal tap involves placing a hollow needle into your lower back to access the spinal canal surrounding your spine. A small amount of cerebrospinal fluid (CSF) is removed to be examined for leukemia cells, an infection, and other abnormalities.
• Cytogenetics: Cytogenetics involves the microscopic examination of the chromosomes of cancer cells to look for chromosomal changes that can identify leukemia cells.
• Fluorescent in situ hybridization (FISH) or polymerase chain reaction (PCR): FISH and PCR are gene studies used to look for changes in certain genes or parts of genes to identify leukemia cells.
  

Assessing Progression

Testing is often an important part of your ongoing and follow-up care. Some tests may be repeated at predetermined intervals. The following tests can help guide treatment, show how your body responds to therapy, and determine disease progression:

• Blood tests
• Flow cytometry
• Polymerase chain reaction (PCR)
• Cytogenetics
• FISH (every three to six months)

Leukemia Classifications

Leukemia classifications are based on the speed of disease progression and the blood cells affected by the disease. Leukemia classifications determine your treatment.

By Speed of Progression

Leukemia classifications based on speed or progression define leukemia as acute or chronic based on the following characteristics:

• Acute leukemia involves immature white blood cells, called blasts, that grow very fast and cause severe symptoms quickly, often in days or weeks. These types of leukemia are very rare.
• Chronic leukemia involves slow-growing blasts that can allow the disease to exist without symptoms for years. Chronic leukemia tends to be less severe than acute leukemia.
  

By Cell Type

Leukemia classifications based on cell type define leukemia as being myeloid or lymphocytic using the following criteria:

• Myeloid leukemia develops in precursors to neutrophils and monocytes, two types of white blood cells that help fight fungal and bacterial infections. Myeloid stem cells also produce precursors to red blood cells and platelets, so these cell lines may also be affected.
• Lymphocytic leukemia develops in mature stem cells that develop into B lymphocytes, T-lymphocytes, or natural killer (NK) cells, which. produces antibodies or other substances that fight infections.
  

Leukemia Staging

Leukemia staging involves the process of identifying how much cancer is in your body and how far it has spread. It is used to create a prognosis and determine a treatment plan based on these characteristics. Leukemia staging defines your diagnosis in a language that everyone in your healthcare team understands.

While the staging of most types of cancer involves an assessment of tumor size and spread, leukemia staging, except for chronic lymphocytic leukemia (CLL), is based on a different set of criteria because it involves your blood cells. Each type of leukemia has a standard system for stating. The factors involved in leukemia prognosis and staging include:

• White blood cell or platelet count
  
• History of prior blood disorders
• Age (advanced age may negatively affect prognosis)
• Chromosome mutations or abnormalities
• Results of bone marrow tests
  
• Enlarged liver or spleen
• Spleen and lymph node size

Leukemia Treatment

Leukemia treatment aims to put the disease into remission and eventually achieve a cure. There are several options for treatment. Your treatment regimen is based on the following factors:

• Type of leukemia
• Disease subtype, phase, category, and stage
• Cytogenetic analysis results
• General health at diagnosis
• Symptoms of your disease
• White cell count
• Location of the cancer cells
• Rate of disease progression
• History of another type of cancer and chemotherapy treatment
• Spread of leukemia into your blood or other parts of your body
  
• Impact of treatment on your quality of life
• Presence of pregnancy

Based on these factors, your personalized leukemia treatment plan will include one or more of the following therapies:

• Watchful waiting: Your condition is closely monitored. While it does not include a specific therapy, it involves regular testing and physical exams to track your condition until symptoms develop. Watchful waiting may be appropriate for CLL.
• Chemotherapy: Chemotherapy is the primary form of treatment for many types of leukemia. A course of chemotherapy often involves the administration of several drugs that destroy tumor cells in different ways. Chemotherapy uses drugs to destroy or slow the progression of fast-growing cancer cells in a certain area or throughout your body.
• Radiation therapy: Radiation therapy uses high-powered waves to break down and destroy the genetic material (DNA) inside cancer cells. It can also help relieve discomfort from an enlarged liver or spleen or damage caused by leukemia cells in your bone marrow.
• Targeted therapy: Targeted therapy uses drugs or other substances to identify and attack specific types of cells involved in the growth and division of cancer cells while reducing the risk of harming normal cells. Targeted therapies all interfere with the growth and survival of cancer cells, though they do not kill cancer cells.
• Bone marrow/stem cell transplants: Bone marrow and stem cell transplants, or hematopoietic cell transplants, involve infusing healthy stem cells to replace damaged ones. Treatment may first be given to destroy the abnormal stem cells.
• Immunotherapy: Immunotherapy uses the abilities of your immune system to fight cancer cells with human-made, donor, genetically modified versions of antibodies, which are proteins that combat infection. These substances help your immune system react to and destroy cancer cells by attaching to a specific target. Examples of immunotherapy include monoclonal antibodies, T-cell therapies, and donor lymphocyte infusions.
• Clinical trials: Clinical trials help advance different aspects of leukemia treatment. While treatments may be experimental, they can offer options for treatment for leukemia cases that haven't responded to established treatments.
  

Is Leukemia Curable?

Leukemia is described as cured when you remain in remission, a state without detectable signs of cancer in your bone marrow or blood counts, for an extended period of time. When you reach this stage, you have an extremely low chance of the disease recurring.

Outlook for Leukemia

The average five-year relative survival rate for people diagnosed with leukemia in the United States is 65%. This describes the percentage of people who are alive five years after they were diagnosed with or started treatment for leukemia. However, this rate does not reflect individual cases and can vary based on many factors, including type of leukemia:

• Chronic lymphocytic leukemia (CLL) five-year survival rate is 85.4%.
• Acute lymphocytic leukemia (ALL) five-year survival rate is 70.8% for all ages but over 90% for children
• Chronic myeloid leukemia (CML) five-year survival rate is 67.8%.
• Acute myeloid leukemia (AML) five-year survival rate is 27.6%.

The survival rate does not determine your individual prognosis. Other factors that can impact your prognosis include the following:

• Your age
• The aggressiveness of your leukemia
• Other medical conditions
• How early cancer was detected
  
• Complications from your disease or treatment
• Your activity level

Living With Leukemia: Support and Resources

There are many aspects to living with leukemia. You will have to manage a wide range of physical and emotional challenges in maintaining your well-being from diagnosis through treatment and for years into your survivorship.

Living with leukemia involves adopting strategies that can help you succeed. To do so, it's important to remember that you're not alone. Discuss your concerns with your healthcare provider to determine whether they are realistic and how to address them.

Take advantage of offers from caregivers who reach out to offer support. These connections can help you feel less isolated and avoid feelings of depression.

Seek out other resources, like community-based or online support groups, to connect with people with the same experiences and concerns. Look for blogs, podcasts, and social media groups that can provide support that can benefit you.

The following organizations are among the leading groups providing support and resources for people with leukemia:

• American Cancer Society
• Cancer Care
• Leukemia Research Foundation
• National Cancer Institute
• The Leukemia and Lymphoma Society

Summary

Leukemia begins in your bone marrow when defective blood stem cells grow faster than normal and survive longer than normal. As their numbers increase, leukemia cells prevent the growth of healthy red blood cells and platelets.

There are many forms of this disease. The onset of symptoms can move quickly or slowly, based on the type of leukemia.

With fewer healthy cells, your body loses its power to fight infection. The effect leaves you more likely to suffer from diseases. As the number of abnormal cells grows, they spill into your bloodstream and spread to other areas of your body.

While chemotherapy is the primary treatment method, there are many ways to attack this disease. Clinical trials offer the chance to gain from research into new treatments if standard choices fail.