Leukemia

What is Leukemia?

Leukemia is a cancer of blood cells and bone marrow. In leukemia, abnormal white blood cells multiply uncontrollably in the bone marrow. Eventually the abnormal cells replace healthy blood cells. When this happens, it prevents healthy red and white blood cells and platelets from developing. Fewer healthy cells means the body can’t fight infections, carry oxygen or help with clotting.

Leukemia can be acute or chronic. Acute leukemia is fast growing and can get worse quickly without treatment. Chronic leukemia grows more slowly and typically gets worse over time. Leukemia accounts for  about 3% of all new cancer diagnoses, according to the National Cancer Institute.

The disease is also classified by the type of white blood cell that is affected. Some types affect the lymphoid cells, which are part of the immune system. Other types affect myeloid cells, which help form red blood cells, white blood cells and platelets. White blood cells are an important part of the immune system that fights off bacteria and viruses. Platelets clot to stop bleeding and help immune responses.

According to the Cancer Research Institute, leukemia occurs most often in people over 55. It is the most common cancer in children under 15. Doctors don’t know the exact causes of leukemia. The disease seems to develop from a combination of genetic and environmental factors. Leukemia is highly treatable. Many people can achieve long-term remission with treatment.

Types of Leukemia

• Acute lymphocytic leukemia (ALL): The most common type of leukemia in children. It can also occur in adults. ALL is a rapidly progressing cancer and requires immediate treatment.
• Acute myelogenous leukemia (AML): The most common type of acute leukemia in adults. It can also occur in children. AML gets worse quickly and treatment needs to start immediately after diagnosis.
• Chronic lymphocytic leukemia (CLL): The most common chronic adult leukemia. You may have it for years without needing treatment because it is slower moving. It is most common in adults older than 55.
• Chronic myelogenous leukemia (CML): Mainly affects adults. You may have no symptoms for months or years before leukemia cells start to grow more quickly. It is slow progressing illness.
• Other types: Some people may have rarer types of leukemia. These include hairy cell leukemia, myelodysplastic types, and myeloproliferative forms.

Causes of Leukemia

Leukemia occurs when the genetic material (DNA) in bone marrow changes. The cause of changes to DNA is unknown.

Risk Factors

Different types of leukemia have different risk factors. In general, the risk of developing leukemia goes up as you age. Other risk factors include:

• Exposure to certain chemicals
• Exposure to high levels of radiation
• Family history of leukemia
• Genetic disorders
• Previous cancer treatment with chemotherapy
• Smoking

Genetics

Some genes help control how cells grow, make new cells or fix mistakes in DNA. Cells can grow out of control when these genes don’t work correctly. Usually, several different genes inside the bone marrow develop mutations before causing leukemia. In some types of cancer, people inherit genetic mutations that increase risk. Leukemia is most commonly caused by gene mutations that happen during a person’s lifetime.

Prevention

There is no guaranteed way to prevent leukemia. The exact cause is unknown. You can reduce your risk by avoiding exposure to hazardous chemicals like benzene and toluene.

Signs and Symptoms

Leukemia symptoms depend on the type of leukemia. Some symptoms are similar to signs of the flu and other common illnesses. See a doctor if you have symptoms that worry you.

Common symptoms include:

• Bone pain
• Easy bleeding or bruising
• Enlarged liver or spleen
• Excessive sweating
• Fatigue and weakness
• Fever or chills
• Frequent infections
• Regular nosebleeds
• Small red spots under the skin
• Swollen lymph nodes
• Unexplained weight loss

Diagnosis

Leukemia is sometimes identified during blood tests for other conditions. If you have symptoms, your doctor will perform a physical exam and take your medical history.

Tests to diagnose leukemia include:

Lab Tests

Blood tests: Your doctor may do a complete blood count (CBC). This test measures red blood cells, white blood cells, platelets, and hemoglobin.

Bone marrow tests: This test takes a sample of your bone marrow (the spongy tissue inside the bone) and bone. The sample is examined under a microscope to look for signs of leukemia.

Genetic tests: These tests are used to check for gene changes that could lead to cancer. Your team may look for specific genetic changes, such as BCR-ABL in CML or FLT3/IDH in AML, to guide treatment options.

Diagnostic Procedures

Lumbar puncture: After diagnosing leukemia, your doctor may do this test to find out if the cancer has spread. This test collects a sample of fluid from the brain and spinal cord to analyze.

Staging Leukemia

Staging leukemia is different from other cancers where tumors are present. Because leukemia is a blood cancer, it does not have measurable tumors or form masses. ALL and AML are classified by subtypes instead of stages.

CLL is one of the only types of leukemia that uses a defined staging system, known as the Rai system:

• Stage 0: High white blood cell counts without symptoms. Patients may not need treatment at this stage.
• Stage I: Swollen lymph nodes, without low red blood cell  or low platelet count.
• Stage II: Enlarged spleen or liver along with swollen lymph nodes.
• Stage III: Anemia due to   leukemia replacing red blood cells in the bone marrow.
• Stage IV: Low platelet counts due to leukemia replacing platelet producing cells in the bone marrow. 

CML uses phases instead of staging:

• Chronic Phase: Mild or no symptoms, usually responds to treatment
• Accelerated Phase: Cancer is more aggressive and has symptoms like fever and weight loss. Responds less to treatment.
• Blastic Phase: This phase has more than 20% of blasts (immature blood cells) in blood or marrow.

Treatment

Treatment for leukemia depends on:

• Type of leukemia
• Age
• Overall health
• Other factors

Your care team will work to determine the best treatment for you. Treatment options may include:

• Chemotherapy: This treatment uses medicines to destroy cancer cells. It can be given by mouth, as a shot, or by IV. Because chemotherapy can also affect healthy cells, it may have a lot of side effects.
• Chemotherapy with stem cell transplant: Chemotherapy may be combined with stem cell transplant for certain kinds of acute leukemia. Stem cells are cells that can develop into many different types of cells within the body. A transplant puts healthy blood stem cells back into the body. This usually allows doctors to use a higher dose of chemotherapy.
• Immunotherapy: This is a treatment that uses medications to help the immune system find and attack cancer cells. Immunotherapy may be used when other treatments haven’t worked.
• Radiation: This type of therapy uses high-energy particles or waves to destroy cancer cells. It may be used in combination with other treatments. Radiation is done either internally with radioactive substances or externally with a special machine.
• Targeted therapy: This treatment is a precise way of targeting specific changes or mutations in cancer cells. It can stop cancer cells from growing and spreading while preventing damage to healthy cells. For example, IDH and FLT3 inhibitors are used to treat AML by blocking the enzymes. . There are many different types of targeted therapy. More testing may be needed to determine if your cancer will respond to targeted therapy.

Supportive care may be necessary for the physical side effects of leukemia treatment, such as pain management, infection prevention and good nutrition.

Lifestyle Management

Lifestyle management is important during leukemia treatment to maintain your physical and emotional well-being. Preventing infections is one of the most important components of lifestyle management. Eating a nutritious diet, exercising and avoiding tobacco can help. You can find other patient resources on living with leukemia on the Blood Cancer United website.

Clinical Trials

Clinical trials help determine new treatment options for leukemia. Patients with leukemia have access to clinical trials. Speak with your doctor to find out if a clinical trial may be a good fit for you.

When to See a Specialist

If you or a loved one has symptoms or a family history of leukemia, it’s important to be evaluated by a hematologist.

At National Jewish Health in Golden and Thornton, Colorado, our hematologists evaluate and treat chronic leukemia in adult patients. Learn more about our Cancer Care program or use the button below to make an appointment.