What is leukemia?

Leukemia is a type of cancer of the blood cells. It starts when cells in the bone marrow become leukemia cells. Over time, these cells crowd out the healthy blood cells in your blood, bone marrow, and other tissues. There are many different kinds of leukemia. The type of treatment you receive depends on the type of leukemia you have.

Leukemia is usually treated with medicines, such as chemotherapy. In some cases other treatments, such as radiation therapy or a stem cell transplant, may be needed. Targeted therapy and immunotherapy are also used to treat leukemia. Your doctor will talk to you about what type of leukemia you have and what kinds of treatment may be best for you.

Your bone marrow is where stem cells grow. These stem cells become white blood cells, red blood cells, and platelets.

In most cases of leukemia, there are too many abnormal white blood cells. These leukemia cells crowd out the normal blood cells in your bone marrow and build up in your lymph nodes, liver, and spleen.

When the leukemia cells crowd out your normal cells, your blood can't do its job. You may bleed or bruise easily, have more infections, and feel very tired.

Remission

Leukemia can go away. People sometimes call this a "cure." But your doctor may use the term "remission" instead of "cure" when talking about the effectiveness of your treatment. Many people who have leukemia are successfully treated, but the term remission is used because cancer can return (recur). It is important to discuss the possibility of recurrence with your doctor.

Symptoms of acute leukemia depend on how much the cancer has grown. They may include:

• A new lump or swollen gland in your neck, under your arm, or in your groin.
• Frequent nosebleeds, bleeding from the gums or rectum, more frequent bruising, or very heavy menstrual bleeding.
• Frequent fevers.
• Night sweats.
• Bone pain.
• Unexplained appetite loss or recent weight loss.
• Feeling tired a lot without a known reason.
• Swelling and pain on the left side of the belly.

The chronic forms of leukemia often cause no symptoms until much later in the disease. And when symptoms appear, they usually appear gradually.

There are several different types of leukemia. In general, leukemia is grouped by how fast it gets worse and what kind of white blood cell it affects.

• It may be acute or chronic. Acute leukemia gets worse very fast and may make you feel sick right away. Chronic leukemia gets worse slowly and may not cause symptoms for years.
• It may be lymphocytic or myeloid.
  • Lymphocytic (or lymphoblastic) leukemia affects young white blood cells called lymphoblasts. These normally become B lymphocytes, T lymphocytes, or natural killer cells.
  • Myeloid leukemia affects young blood cells called myeloid stem cells. These normally become myeloblasts, red blood cells, or platelets.

Treatment for leukemia is based on the type of leukemia and whether it has spread. It's also based on other things, such as your overall health. Treatment options may include chemotherapy and other medicines, radiation therapy, stem cell transplant, targeted therapy, and immunotherapy.

There is no known way to prevent most types of leukemia.

Some types of leukemia may be prevented by avoiding high doses of radiation, exposure to the chemical benzene, smoking and other tobacco use, or certain types of chemotherapy used to treat other types of cancer.

Finding the type of leukemia

If your blood work points to possible leukemia, your doctor will want to find out what kind you might have. Your treatment plan will depend on the specific kind of leukemia that you have.

• A blood test is usually enough to find signs of chronic lymphocytic leukemia (CLL).
• Tests that look closely at unusual cells, chromosomes, or proteins on cells can show what type or subtype of leukemia you have. These tests include:
  • A test that looks for certain changes in the cell chromosomes from a sample of blood or bone marrow (cytogenetic analysis).
  • A test that compares cancer cells to normal blood cells to find the specific kind of leukemia (immunophenotyping).
  • A test to look for genes that are "turned on" in several types of leukemia, such as acute myelogenous leukemia (AML). This test is called a reverse transcription-polymerase chain reaction test, or RT-PCR.

These tests can help guide treatment. Sometimes they can help your doctor and you know whether your leukemia is likely to go into remission or come back. In some cases, the tests can predict survival rates.

Your doctor may also order other tests, including:

• Chest X-rays, to find out if leukemia or an infection is the cause of lung problems such as persistent coughing, coughing up blood, chest pain, or trouble breathing.
• CT scan of the head, chest, and belly, to find out if leukemia has spread there.
• Lumbar puncture, to find out if leukemia cells are in your cerebrospinal fluid (CSF).
• MRI of the brain, to look into symptoms such as confusion, paralysis, numbness, vision problems, vertigo, or headaches. Those symptoms could mean that leukemia has spread to the brain.
• A biopsy of a lymph node or other tissues, to look for leukemia cells.

Health professionals who can evaluate symptoms of leukemia include the following:

• Family medicine physician
• Internist
• Nurse practitioner
• Physician assistant

The diagnosis of leukemia will be done by a medical oncologist, pediatric oncologist, or hematologist. These specialists also treat leukemia.

• Take your medicines exactly as prescribed. Call your doctor if you think you are having a problem with your medicine.
• Follow your doctor's instructions to relieve pain. Pain from cancer and surgery can almost always be controlled. Use pain medicine when you first notice pain, before it becomes severe.
• Eat healthy food. If you do not feel like eating, try to eat food that has protein and extra calories to keep up your strength and prevent weight loss.
• Get some physical activity every day, but do not get too tired.
• Get enough sleep, and take time to do things you enjoy. This can help reduce stress.
• Think about joining a support group. Or discuss your concerns with your doctor or a counselor.
• If you are vomiting or have diarrhea:
  • Drink plenty of fluids to prevent dehydration. Choose water and other clear liquids. If you have kidney, heart, or liver disease and have to limit fluids, talk with your doctor before you increase the amount of fluids you drink.
  • When you are able to eat, try clear soups, mild foods, and liquids until all symptoms are gone for 12 to 48 hours. Other good choices include dry toast, crackers, cooked cereal, and gelatin dessert, such as Jell-O.
• If you have not already done so, prepare a list of advance directives. Advance directives are instructions to your doctor and family members about what kind of care you want if you become unable to speak or express yourself.

Some things can increase your chances of getting leukemia. These things are called risk factors. But many people who get leukemia don't have any of these risk factors. And some people who have risk factors don't get this cancer.

General risk factors for leukemia

• Being exposed to high levels of radiation
• Chemotherapy or radiation used to treat a previous cancer
• Having a genetic condition, such as Down syndrome
• Having changes in certain genes or chromosomes

Other risk factors for AML

• Being exposed to chemicals, such as benzene and formaldehyde
• A history of smoking
• Having a virus that attacks the immune system, like human immunodeficiency virus (HIV)

Other risk factors for CLL

• Your family history. In some cases, CLL runs in families.
• Being middle-aged or older, male, and white

Other risk factors for CML

• Having a gene change (mutation) called the Philadelphia chromosome

Leukemia is cancer of the blood cells. It starts in the bone marrow, the soft tissue inside most bones. Bone marrow is where blood cells are made.

Experts don't know what causes leukemia in most people. But they think that most leukemia happens because of things in the environment and in a person's genes.

Some things may increase the risk, such as having certain genetic conditions or being exposed to large amounts of radiation or certain chemicals.