Leukemia

Leukemias are cancers of white blood cells that occur in the blood and bone marrow. When leukemia develops, the bone marrow makes too many abnormal white blood cells, crowding out any existing healthy blood cells. Leukemias are categorized into two groups: acute (faster growing) and chronic (slower growing).

There are two major types of acute leukemia:

Acute Myeloid Leukemia (AML): is the most common type of acute leukemia, usually occurring in older adults, and is very aggressive. About 19,000 cases of AML are diagnosed each year and is slightly more common in men than in women.

Acute Lymphocytic Leukemia (ALL): is the most common type of leukemia in children, but it can also affect adults. While most cases of ALL occur in children, most deaths from ALL occur in adults. Children may do better because of differences in childhood and adult ALL in the disease itself or because children’s bodies can often handle aggressive treatment better than adult’s.

There are two major types of chronic leukemia:

Chronic Myeloid Leukemia (CML): is uncommon and accounts for only 10% of leukemia cases. This disease is almost always caused by the development of an abnormal chromosome, called the Philadelphia chromosome. With treatment, most patients achieve remission.

Chronic Lymphocytic Leukemia (CLL): is the most common type of leukemia, accounting for one-third of all leukemia cases, and is typically found in older adults. It is very slow to progress and can often be observed for an extended period without requiring treatment.

Leukemia symptoms vary depending on the type of leukemia, but common symptoms include fever or chills; persistent fatigue or weakness; frequent or severe infections; unexplained weight loss; swollen lymph nodes or enlarged liver or spleen; easy bleeding or bruising; recurrent nosebleeds; tiny red spots on the skin; excessive sweating especially at night; bone pain or tenderness.

Leukemia is usually found in routine blood tests, however physical exams or bone marrow biopsies may be needed for an accurate diagnosis. Treatment for leukemia can be complex and depend on many factors, such as the type of leukemia, and whether it has spread to other parts of the body like the central nervous system.

Treatment Options

There are several types of leukemia which are classified by the type of cell the cancer starts in and how fast the cancer is growing. The type of leukemia you have will help your care team determine the best treatment for you. Below you’ll find the typical treatments for the main subtypes of leukemia. While these are the most commonly used treatments for each leukemia type, your physician will recommend the treatment that best fits your health needs and goals.

Acute Lymphocytic Leukemia (ALL)

Chemotherapy is the main treatment used for most people diagnosed with ALL. Chemotherapy uses drugs that travel through the bloodstream to target cancer cells throughout the body. Treatment usually takes place in three phases:

• Induction: This is a short and intensive treatment period taking place over a month.
• Consolidation: This is an intensive treatment period that usually lasts for a few months.
• Maintenance: This is a less intensive treatment that usually takes place over two years.
• Each treatment phase is followed by a period of rest to allow your body time to recover. In some cases, your physician may recommend targeted therapy or immunotherapy drugs, or a stem cell transplant.

Chronic Lymphocytic Leukemia (CLL)

Treatment options for CLL can vary. Cancer fighting drugs are often used as an initial treatment for this
type of leukemia. This may include:

• Monoclonal antibodies: These are synthetic versions of immune system proteins that latch onto specific substances on the surface of leukemia cells.
• Targeted drugs: These drugs work on targets within the cancer cells to stop growth.
• Chemotherapy: This treatment kills cancer cells by stopping the cell life cycle. It is less specific than monoclonal antibodies or targeted drugs.
• Surgery is rarely used to treat CLL, but your provider may recommend it if your spleen is enlarged.

Acute Myeloid Leukemia (AML)

Chemotherapy is the main treatment used to treat AML. Chemotherapy for this type of leukemia is usually given in two phases:

• Induction: This is an intensive treatment that usually lasts about a week. This goal of this phase is to eliminate leukemia cells in the blood and reduce the number of leukemia cells in the bone marrow.
• Consolidation: After a period of rest following the induction stage, chemotherapy is given in cycles to destroy the remaining leukemia cells.
• For some patients, a third phase (maintenance) may use low doses of chemotherapy over the course of months or years. This is done to prevent leukemia from returning.

Chronic Myeloid Leukemia (CML)

Targeted therapies with drugs known as tyrosine kinase inhibitors (TKIs) are the standard treatment for CML. These cancer cells contain an abnormal gene that produces a protein which leads to uncontrolled cell growth and division. TKIs target this specific protein to stop growth. If initial treatment with TKIs does not stop the cancer growth, your physician may increase the dose of the drug or switch to another type of TKI. Chemotherapy or a stem cell transplant may be an option for some patients.

Chronic Myelomonocytic Leukemia (CMML)

Stem cell transplants are the only curative treatment for CMML. The patient will receive high–dose chemotherapy, often along with radiation therapy to the entire body, to destroy the cells in the bone marrow. This is followed by the stem cell transplant, which gives the patient new, healthy blood–forming cells. If a stem cell transplant cannot be done, supportive care like transfusions and antibiotics to treat infections can be used to relieve symptoms, limit complications, and reduce side effects.

Radiation Therapy for Leukemia

Radiation therapy uses concentrated rays of high–energy to target and destroy cancer cells while minimizing the effect on healthy cells. While radiation therapy is not usually part of the main treatment used to treat most types of leukemia, it can be used in some situations. Your physician may recommend external beam radiation. This treatment uses a machine to deliver carefully focused rays of energy from outside of the body. It is used to destroy leukemia cells or to help ease pain and/or symptoms from an enlarged spleen or lymph nodes. If you are receiving radiation before a stem cell transplant, your physician may recommend total body irradiation. With this treatment, low doses of radiation are used to deliver treatment to target cancer cells throughout the body.

Scientists don’t understand the exact causes of leukemia. It seems to develop from a combination of genetic and environmental factors. However, there are a few known risk factors: previous chemotherapy or radiation therapy treatments, genetic disorders such as Down syndrome, exposure to certain chemical such as benzene, family history of leukemia and smoking.