Leukemia is cancer that starts in the tissues that forms blood.
The types of leukemia can be grouped based on how quickly the disease develops and gets worse. Leukemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):
- Chronic leukemia: Early in the disease, the leukemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukemia during a routine checkup – before there are any symptoms. Slowly, chronic leukemia gets worse. As the number of leukemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.
- Acute leukemia: The leukemia cells can’t do any of the work of normal white blood cells. The number of leukemia cells increases rapidly. Acute leukemia usually worsens quickly.
The types of leukemia also can be grouped based on the type of white blood cell that is affected. Leukemia can start in lymphoid cells or myeloid cells. Leukemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukemia. Leukemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukemia.
There are four common types of leukemia:
- Chronic lymphocytic leukemia (CLL): CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.
- Chronic myeloid leukemia (CML): CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukemia each year. It mainly affects adults.
- Acute lymphocytic (lymphoblastic) leukemia (ALL): ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukemia each year. ALL is the most common type of leukemia in young children. It also affects adults.
- Acute myeloid leukemia (AML): AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukemia each year. It occurs in both adults and children.
- Hairy Cell Leukemia: A rare type of leukemia in which abnormal B-lymphocytes (a type of white blood cell) are present in the bone marrow, spleen, and peripheral blood. When viewed under a microscope, these cells appear to be covered with tiny hair-like projections.
Doctors sometimes find leukemia after a routine blood test. If you have symptoms that suggest leukemia, your doctor will try to find out what’s causing the problems. Your doctor may ask about your personal and family medical history.
You may have one or more of the following tests:
- Physical exam: Your doctor checks for swollen lymph nodes, spleen, or liver.
- Blood tests: The lab does a complete blood count to check the number of white blood cells, red blood cells, and platelets. Leukemia causes a very high level of white blood cells. It may also cause low levels of platelets and hemoglobin, which is found inside red blood cells.
- Biopsy: Your doctor removes tissue to look for cancer cells. A biopsy is the only sure way to know whether leukemia cells are in your bone marrow. Before the sample is taken, local anesthesia is used to numb the area. This helps reduce the pain. Your doctor removes some bone marrow from your hipbone or another large bone. A pathologist uses a microscope to check the tissue for leukemia cells.
There are two ways your doctor can obtain bone marrow. Some people will have both procedures during the same visit:
- Bone marrow aspiration: The doctor uses a thick, hollow needle to remove samples of bone marrow.
- Bone marrow biopsy: The doctor uses a very thick, hollow needle to remove a small piece of bone and bone marrow.
The tests that your doctor orders for you depend on your symptoms and type of leukemia. You may have other tests:
- Cytogenetics: The lab looks at the chromosomes of cells from samples of blood, bone marrow, or lymph nodes. If abnormal chromosomes are found, the test can show what type of leukemia you have. For example, people with CML have an abnormal chromosome called the Philadelphia chromosome.
- Spinal tap: Your doctor may remove some of the cerebrospinal fluid (the fluid that fills the spaces in and around the brain and spinal cord). The doctor uses a long, thin needle to remove fluid from the lower spine. The procedure takes about 30 minutes and is performed with local anesthesia. You must lie flat for several hours afterward to keep from getting a headache. The lab checks the fluid for leukemia cells or other signs of problems.
- Chest x-ray: An x-ray can show swollen lymph nodes or other signs of disease in your chest.
People with leukemia have many treatment options. The options are watchful waiting, chemotherapy, targeted therapy, biological therapy, radiation therapy, and stem cell transplant. If your spleen is enlarged, your doctor may suggest surgery to remove it. Sometimes a combination of these treatments is used.
The choice of treatment depends mainly on the following:
- The type of leukemia (acute or chronic)
- Your age
- Whether leukemia cells were found in your cerebrospinal fluid
It also may depend on certain features of the leukemia cells. Your doctor also considers your symptoms and general health.
People with acute leukemia need to be treated right away. The goal of treatment is to destroy signs of leukemia in the body and make symptoms go away. This is called a remission. After people go into remission, more therapy may be given to prevent a relapse. This type of therapy is called consolidation therapy or maintenance therapy. Many people with acute leukemia can be cured.
If you have chronic leukemia without symptoms, you may not need cancer treatment right away. Your doctor will watch your health closely so that treatment can start when you begin to have symptoms. Not getting cancer treatment right away is called watchful waiting.
When treatment for chronic leukemia is needed, it can often control the disease and its symptoms. People may receive maintenance therapy to help keep the cancer in remission, but chronic leukemia can seldom be cured with chemotherapy. However, stem cell transplants offer some people with chronic leukemia the chance for cure.
Your doctor can describe your treatment choices, the expected results, and the possible side effects. You and your doctor can work together to develop a treatment plan that meets your medical and personal needs.
You may want to talk with your doctor about taking part in a clinical trial, a research study of new treatment methods. See the Taking Part in Cancer Research section.
Your doctor may refer you to a specialist, or you may ask for a referral. Specialists who treat leukemia include hematologists, medical oncologists, and radiation oncologists. Pediatric oncologists and hematologists treat childhood leukemia. Your health care team may also include an oncology nurse and a registered dietitian.
Whenever possible, people should be treated at a medical center that has doctors experienced in treating leukemia. If this isn’t possible, your doctor may discuss the treatment plan with a specialist at such a center.
Before treatment starts, ask your health care team to explain possible side effects and how treatment may change your normal activities. Because cancer treatments often damage healthy cells and tissues, side effects are common. Side effects may not be the same for each person, and they may change from one treatment session to the next.
People with chronic lymphocytic leukemia who do not have symptoms may be able to put off having cancer treatment. By delaying treatment, they can avoid the side effects of treatment until they have symptoms.
If you and your doctor agree that watchful waiting is a good idea, you’ll have regular checkups (such as every 3 months). You can start treatment if symptoms occur.
Although watchful waiting avoids or delays the side effects of cancer treatment, this choice has risks. It may reduce the chance to control leukemia before it gets worse.
You may decide against watchful waiting if you don’t want to live with an untreated leukemia. Some people choose to treat the cancer right away.
If you choose watchful waiting but grow concerned later, you should discuss your feelings with your doctor. A different approach is nearly always available.
Many people with leukemia are treated with chemotherapy. Chemotherapy uses drugs to destroy leukemia cells.
Depending on the type of leukemia, you may receive a single drug or a combination of two or more drugs.
You may receive chemotherapy in several different ways:
- By mouth: Some drugs are pills that you can swallow.
- Into a vein (IV): The drug is given through a needle or tube inserted into a vein.
- Through a catheter (a thin, flexible tube): The tube is placed in a large vein, often in the upper chest. A tube that stays in place is useful for patients who need many IV treatments. The health care professional injects drugs into the catheter, rather than directly into a vein. This method avoids the need for many injections, which can cause discomfort and injure the veins and skin.
- Into the cerebrospinal fluid: If the pathologist finds leukemia cells in the fluid that fills the spaces in and around the brain and spinal cord, the doctor may order intrathecal chemotherapy. The doctor injects drugs directly into the cerebrospinal fluid. Intrathecal chemotherapy is given in two ways:
- Into the spinal fluid: The doctor injects the drugs into the spinal fluid.
- Under the scalp: Children and some adult patients receive chemotherapy through a special catheter called an Ommaya reservoir. The doctor places the catheter under the scalp. The doctor injects the drugs into the catheter. This method avoids the pain of injections into the spinal fluid.
Intrathecal chemotherapy is used because many drugs given by IV or taken by mouth can’t pass through the tightly packed blood vessel walls found in the brain and spinal cord. This network of blood vessels is known as the blood-brain barrier.
Chemotherapy is usually given in cycles. Each cycle has a treatment period followed by a rest period.
You may have your treatment in a clinic, at the doctor’s office, or at home. Some people may need to stay in the hospital for treatment.
People with chronic myeloid leukemia and some with acute lymphoblastic leukemia may receive drugs called targeted therapy. Imatinib (Gleevec) tablets were the first targeted therapy approved for chronic myeloid leukemia. Other targeted therapy drugs are now used too.
Targeted therapies use drugs that block the growth of leukemia cells. For example, a targeted therapy may block the action of an abnormal protein that stimulates the growth of leukemia cells.
Some people with leukemia receive drugs called biological therapy. Biological therapy for leukemia is treatment that improves the body’s natural defenses against the disease.
One type of biological therapy is a substance called a monoclonal antibody. It’s given by IV infusion. This substance binds to the leukemia cells. One kind of monoclonal antibody carries a toxin that kills the leukemia cells. Another kind helps the immune system destroy leukemia cells.
For some people with chronic myeloid leukemia, the biological therapy is a drug called interferon. It is injected under the skin or into a muscle. It can slow the growth of leukemia cells.
You may have your treatment in a clinic, at the doctor’s office, or in the hospital. Other drugs may be given at the same time to prevent side effects.