Leukemia is a cancer of the blood and bone marrow. In simple terms, cancer is defined as the uncontrolled growth of abnormal cells. Cancer can develop anywhere in the body. In leukemia, this rapid, out-of-control growth of abnormal cells takes place in the bone marrow of bones. These abnormal cells then spill into the bloodstream. Unlike other cancers, leukemia generally doesn’t form into a mass (tumor) that can be seen in imaging tests, such as X-rays.
There are many types of leukemia. Some are more common in children; others are more common in adults. Treatment depends on the type of leukemia you have and other factors.
Bone marrow is the soft, spongy tissue in the center cavity of all bones. It is a limited space where all the different types of blood cells are made and where nutrients and other resources are supplied to help these cells grow. Blood cells keep our body healthy and functioning normally. More specifically, the different types of blood cells produced in the bone marrow include:
Hundreds of billions of new blood cells are produced in the bone marrow each day, providing your body with a constant supply of fresh, healthy cells.
Leukemia begins in the developing blood cells in the bone marrow. All blood cells start out as hematopoietic (hemo = blood; poiesis = make) stem cells. The stem cells undergo multiple stages of development until they reach their adult form.
First, blood stem cells develop into either myeloid cells or lymphoid cells. If blood cells were to continue to develop completely normally, the adult forms of these cells are as follows:
As stem cells in bone marrow begin to divide and multiply, they develop into all the needed types of blood cells. In patients with leukemia, cell growth goes "haywire," and there is a rapid growth of abnormal white blood cells.
So inside the bone marrow, blood cells are beginning to multiply and divide into red blood cells, white blood cells and platelets. However, if you have leukemia, one of these blood cell types begins to rapidly multiply, in an out-of-control manner. These abnormal cells – called leukemia cells – begin to take over the space inside the bone marrow. They crowd out the other normal cell types that are trying to develop. This is bad in a number of ways:
Leukemia cells are usually immature (still developing) white blood cells. In fact, the term leukemia comes from the Greek words for "white" (leukos) and "blood" (haima). An excess number of white blood cells are seen when looking at blood through a microscope and the actual appearance of the blood is lighter to the naked eye.
Yes. Doctors classify leukemia by how quickly the disease worsens and by the type of blood cell involved.
By speed of disease development:
By cell type:
There are four major types of leukemia:
In addition to these four main types of leukemia, there also are various subtypes of leukemia. Subtypes of lymphocytic leukemia include hairy cell, Waldenstrom’s macroglobulinemia, prolymphocytic, and lymphoma cell leukemia. Among the subtypes of myelogenous leukemia are myelogenous, promyelocytic, monocytic, erythroleukemia, and megakaryocytic leukemia.
The number of new cases of leukemia diagnosed in the United States each year is about 14 per 100,000 men and women or 61,000 new cases per year. It is the tenth most common cancer according to new cases diagnosed each year. Leukemia accounts for 3.5% of all new cancer cases in the United States.
Leukemia is often considered a disease of children, yet it actually affects far more adults. In fact, the likelihood of developing this cancer increases with age. Leukemia is most frequently diagnosed in people 65 to 74 years of age. Leukemia is more common in men than in women, and more common in Caucasians than in African-Americans. Although leukemia is rare in children, of the children or teens who develop any type of cancer, 30% will develop some form of leukemia.
Leukemia starts when the DNA of a single cell in the bone marrow changes (mutates) and can’t develop and function normally. (DNA is the “instruction code” for the cell’s growth and function. Segments of DNA make up genes, which are arranged on larger structures called chromosomes.) All cells that arise from that initial mutated cell also have the mutated DNA.
What causes the damage to the DNA in the first place is still not known in all cases. Scientists have been able to locate changes in certain chromosomes of patients diagnosed with different types of leukemia.
Although the exact cause of the DNA mutation that leads to leukemia is not fully known, scientists have discovered certain risk factors that may increase your risk of developing leukemia. These risk factors include:
Leukemia can happen to anyone. You may get leukemia and have none of these risk factors. Other people have one or more of these risk factors and never get leukemia.
You cannot “catch” leukemia from someone else. It is not “transmitted” from one person to another.
Yes, however this is uncommon. Genetic disorders such as Down syndrome can increase the risk of leukemia. Scientists have also found other genetic mutations that can increase the risk. How much the risk is increased is not exactly known. Having a relative in your family with leukemia does not mean you or your family members will also develop leukemia. In fact, in most cases, there’s no family history of leukemia. However, if you or a family member has a genetic condition, tell your doctor. Your doctor may recommend genetic testing or counseling.
Your symptoms depend, in part, on what type of leukemia you have. However, common signs and symptoms include:
Keep in mind that if you have a chronic form of leukemia, you may not have any noticeable symptoms in the early stages of this cancer.
Your doctor will conduct a physical exam, order blood tests and, if results are suspicious, order imaging tests and a bone marrow biopsy.
Physical exam: Your doctor will ask about any symptoms you are experiencing and check for swollen lymph nodes. (You have lymph nodes throughout your body but some can be more easily felt, such as those in your neck or under your armpits). Your doctor may also look at your gums to see if they are swollen or bleeding, look for bruises or a tiny red skin rash (petechiae) and signs of an enlarged spleen. You may not have many or any obvious symptoms if you have early-stage chronic leukemia. Symptoms can also be relatively common to many other illnesses, such as simply feeling tired or having flu-like symptoms that do not improve.
Complete blood count (CBC): This blood test gives details about red blood cells, white blood cells and platelets. If you have leukemia you will have lower than normal counts of red blood cells and platelets, and higher than normal counts of white blood cells. Some leukemia cells may be found. (Leukemia cells are the still developing immature cells – usually white blood cells – that rapidly multiply in bone marrow and spill over into the bloodstream.)
Blood cell examination. Other blood samples may be taken and checked for type and shape of blood cells and examined for other substances released by your body’s organs and tissues that may be signs of disease. Other tests may help identify chromosomal abnormalities and other markers on the cells that help identify the type of leukemia.
Bone marrow biopsy (also called bone marrow aspiration): If your white blood cell count is abnormal, your doctor will get a sample of cells from your bone marrow. During this procedure, a long needle is used to draw out some fluid from the marrow of your bone, usually from an area near your hip (pelvic bone). A laboratory then examines the blood cells in the fluid under a microscope. A bone marrow biopsy helps determine the percentage of abnormal cells in the bone marrow, which confirms the diagnosis of leukemia.
During a bone marrow biopsy, fluid is removed from the bone marrow and examined under a microscopic.
Imaging and other tests: Your doctor may order a chest X-ray, CT scan, or magnetic resonance imaging (MRI) scan if you have symptoms that indicate a complication of the leukemia. A lumbar puncture (also called a spinal tap) may be ordered to see if the cancer had spread to the spinal fluid surrounding the brain and spinal cord.
Treatments for leukemia depend on the type of leukemia you have, your age and overall health, and if the leukemia has spread to other organs or tissues. There are five common treatment categories. They include:
Note: A treatment plan will be developed specifically for you. Several of the treatment methods described above will be a part of your treatment plan. Your treatment depends on your age, overall health, type of leukemia and other unique features of the leukemia, response to initial treatment and many other factors. Your healthcare team will determine a treatment plan they hope will be most successful for you.
Some leukemia treatment is delivered in three phases. Each phase has a specific goal.
(Treatment can be also directed at the brain and spinal cord [the central nervous system] during each of these phases. This is done to kill cancer cells that hide in these areas of the body where the chemotherapy cannot reach. These “hidden” cancer cells are a reason leukemia comes back or relapses.)
Other leukemia treatments do not have phases and are given indefinitely. They are continued as long as they are working to combat the leukemia and the patient is tolerating the treatment well.
Treatment is resumed or changed if leukemia comes back or relapses.
While this seems like a straight-forward question, the answer is a little more complicated. It’s understandable that you want to know if you or your loved one will survive a diagnosis of leukemia. Unfortunately, it’s difficult to make general predictions. There are many factors to consider that affect your chance of recovery, including:
The general good news is that although the number of new cases of leukemia in the United States has remained relatively steady or slightly increased since the 1970s, survival rate has also improved.
The National Cancer Institute reports the following survival data for the four main types of leukemia:
|Types of Leukemia||ALL||AML||CLL||CML|
|5- year survival rate*||68.60%||28.30%||85.10%||69.20%|
|Number of deaths per 100,000 persons||0.4||2.8||1.2||0.3|
|Death is highest among those aged||65-74||65+||75+||75+|
ALL = acute lymphocytic leukemia; AML = acute myelogenous leukemia; CLL = chronic lymphocytic leukemia; CML = chronic myelogenous leukemia
* survival compares patients diagnosed with cancer vs people of same age, race and sex who are cancer free.
Data source: SEER Cancer Statistics Review, 1975-2016, National Cancer Institute. Bethesda, MD.
It’s important to keep in mind that treatment results and long-term outcome vary for each patient.
From a scientific standpoint, “cured” is a hopeful goal, yet is somewhat difficult to define in the field of cancer. Are you “cured” after five years of being free of cancer? After 10 years? Does cure mean that you no longer have any negative effects on the quality of your life from your treatment?
Cancer researchers usually are more comfortable talking about achieving long-term remission if you have a diagnosis of cancer. Children and teens, younger adults, people in good health with few other illnesses generally have the best outcomes. Acute lymphoid leukemia represents one of the most dramatic success stories in cancer treatment. According to the Leukemia & Lymphoma Society, nearly 90% of children and 40% of adults diagnosed with ALL can expect a long-term remission.
The answer to “am I cured of my leukemia” will best be answered by your healthcare team over a long period of time. Your team will work closely with you to develop the best treatment plan for your specific type of leukemia and will carefully follow you for many years to come.
It’s important not to miss any of your follow-up appointments. You healthcare team will tell you when and how often you will need to be seen. Follow-up appointments can help manage treatment side effects, check how well treatment is working and make any needed changes in treatment based on a repeat of many of the same tests you took to diagnose the leukemia.
Talk with your doctor and members of your healthcare team about your diagnosis of leukemia. Each case of leukemia in each patient is unique. Take notes and/or bring a friend with you to help take notes and provide support. If you don’t understand something a doctor says to you, ask the doctor to explain it. Your healthcare team wants you to play an active role in your care or care of your loved one with leukemia.
Some of the questions to ask your doctor and team may include:
Yes. To learn more about clinical trials for leukemia, visit these sites:
To find support groups, visit:
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 11/19/2019