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Anemia in People With Cancer

What is anemia?

If your red blood cell count is low, you might be told you have anemia. Anemia means your blood has too little hemoglobin. Hemoglobin is the part of the red blood cell (RBC) that carries oxygen to all the cells in your body. Normal levels of hemoglobin can vary a bit based on age, sex, and which lab does the test.

Doctors often define anemia in adults as a hemoglobin (Hgb) of less than 12 g/dL (grams per deciliter). But many people do not feel much different until their hemoglobin level falls below 11 g/dL, or sometimes even lower. (Hemoglobin is measured with a blood test that’s often done along with a complete blood count, or CBC.)

Symptoms of anemia often start slowly, so you may not even notice them at first. But they get worse as the hemoglobin gets lower. Symptoms can include:

  • Fast heart beat
  • Shortness of breath
  • Trouble breathing when doing things like walking, climbing stairs, or even talking
  • Dizziness
  • Chest pain
  • Swelling in the hands and/or feet
  • Pale skin, nail beds, mouth and gums
  • Extreme tiredness (fatigue)

Severe tiredness and weakness are often the symptoms that bother people most. For more information on fatigue and how to manage it, see Fatigue in People With Cancer.

What causes anemia?

There are many different causes of anemia in people with cancer. Some common causes are:

  • The cancer itself
  • Cancer treatment, such as radiation or chemotherapy
  • Blood loss (this can be slow constant bleeding such as from the intestine or bladder; or fast bleeding, like heavy menstruation or bleeding from a stomach ulcer)
  • Certain vitamins or minerals missing in a person’s diet
  • Low iron levels in the blood
  • Major organ problems (including severe heart, lung, kidney, or liver disease)
  • Red blood cells (RBCs) being destroyed by the body before they’re replaced
  • Chronic kidney disease
  • The body making fewer RBCs
  • Sickle cell disease or thalassemia (inherited disorders that cause the body to destroy too many red blood cells)
  • A combination of any of these factors

There are also some risk factors that may make you more likely to have anemia. These include:

  • Platinum-based chemotherapy (this is a certain group of chemo drugs)
  • Certain tumor types (such as lung or ovary tumors)
  • Having a low hemoglobin level before you had cancer

Tests to look for the cause of anemia

If you have a hemoglobin level lower than 11 g/dL your doctor will ask questions about your past and current medical conditions and do a physical exam. Other tests may be needed to help to find the cause of your anemia. These could include:

  • Blood chemistry tests to check organ function and levels of vitamins and minerals
  • A blood test called a reticulocyte count (Reticulocytes are very young red blood cells just released from the bone marrow, so this test shows how many new red cells your body is making.)
  • A bone marrow exam
  • A blood test to look at your iron levels
  • A test of your stool (feces) to check for blood (called a fecal occult blood test or FOBT)

Your doctor or nurse can use the results of these tests, along with your medical information and physical exam, to get an idea of what might be causing your anemia. Sometimes no cause can be found other than “anemia of chronic disease.” This type of anemia is often found in people with long-lasting problems like congestive heart failure, inflammatory diseases, or cancer.

What problems can anemia cause?

Learning the cause of the anemia is important, but the first thing the doctor needs to know is how severe or how “bad” it is.

Anemia can make you feel very tired because cells in your body are not able to get enough oxygen. In some cases, this lack of oxygen may be severe enough to threaten life. Anemia can also cause your heart to work harder. So if you already have a heart problem, anemia can make it worse.

Severe anemia may mean you have to delay your cancer treatment or have your treatment dose reduced. It can also cause some treatments to not work as well as they should.

Your doctor or nurse may try to figure out your risk of serious problems from the anemia based on any symptoms you are having and your hemoglobin level. If you’re not having symptoms, they will try to figure out how likely you are to have them in the near future. This will be based on a number of things, including:

  • Your hemoglobin level and other lab results
  • The type of cancer treatments you’ve had in the past
  • The chances that any treatments you’re now getting could make the anemia worse
  • Your need for blood transfusions in the past 6 months
  • Whether you have lung, heart, or blood vessel (circulation) problems
  • Your age

If you do not seem to be at risk for problems from anemia, your doctor or nurse will watch your hemoglobin level closely and ask about symptoms each time you visit the office.

How bad is the anemia?

Doctors often rate how severe or how “bad” anemia is based on the amount of hemoglobin in your blood. Even though your symptoms may not match, doctors use this way of ranking anemia when deciding about treatment.

    Mild anemia: hemoglobin between 10 and the lower limit of normal for your age, sex, and the lab
    Moderate anemia:
    hemoglobin 8 to 10 g/dL
    Severe anemia:
    hemoglobin 6.5 to 8 g/dL
    Life-threatening anemia:
    hemoglobin less than 6.5

Some serious symptoms of anemia are:

  • Chest pain
  • Fast heart beat
  • Swelling in your legs
  • Feeling dizzy or lightheaded
  • Having trouble breathing when you exert yourself

If you have any of these symptoms, tell your doctor or nurse right away.

Other medical problems such as heart disease or chronic lung disease may already affect how much oxygen is getting to your body. These conditions along with anemia could increase your risk of serious problems. If your health care team finds that your anemia is a serious threat to your health, you may need a blood transfusion. (See the next section.)

Treating anemia

There are 2 main goals in treating anemia:

  • Treat the cause of the anemia
  • Raise the hemoglobin level so that symptoms get better

Depending on the cause of the anemia, treating it may include things like eating nutrient-rich foods; taking iron, vitamin B12, and/or folic acid supplements; delaying or changing cancer treatment; and stopping any bleeding. (See the section called “What causes anemia?” for more on this.)

Your cancer care team may ask you to try to eat more iron-rich foods. Foods that contain high amounts of iron include dark green, leafy vegetables; sweet potatoes; prunes and raisins; dried apricots and peaches; beans; meat and fish; enriched bread, cereal, and pasta; and seeds. Ask your cancer care team which foods would be best for you. In some cases, a liquid form of iron may be put right into your blood (as an IV infusion).

If the hemoglobin level needs to be raised quickly, a transfusion of red blood cells may be given (discussed in the next section). Some cancer patients whose treatment has caused anemia may be able to use certain drugs to raise their hemoglobin levels, but this takes longer. (See the later section called “Drugs to treat anemia.”)

Talk to your doctor about what treatment is right for you. As with any medical problem, the expected benefits of treatment should always outweigh the possible risks.

Blood transfusions to treat anemia

Red blood cell transfusions are a common way to treat anemia. The need for a blood transfusion depends on how bad your symptoms are and your hemoglobin level. A transfusion is done most often when the hemoglobin level is less than 8 g/dL. This raises the level of hemoglobin quickly to improve symptoms, help the patient feel better, and make sure that enough oxygen is getting to vital organs.

Blood transfusions fix the problem very quickly, but they do carry a small chance of serious risks. The most common problem is a transfusion reaction. This happens when a patient’s immune system attacks proteins on the foreign blood cells. Most of these reactions are minor and can be treated, but sometimes they can be more serious. These often look like allergic reactions.

Transfusion-related lung injury is one of the more serious risks. It can cause trouble breathing and require treatment in the hospital. Another possible risk is the chance of getting certain germs, such as the hepatitis B virus. But the careful blood testing and screening that’s used today have made the risk of infections very small.

In some people, transfusion-related circulatory overload (TACO) can happen if blood is given too quickly for the heart to handle it. And people who get many blood transfusions (usually more than 25 units of red cells) may end up with too much iron, which would then need to be treated. For more details on transfusions, see Blood Transfusion and Donation.

Drugs to treat anemia

Another way to treat anemia in some patients is to use drugs that tell the body to make more red blood cells. These drugs work like erythropoietin, a hormone that’s made by the kidneys to help the body make its own new red blood cells. The drugs are epoetin, also called Epogen® or Procrit®, and darbepoetin which is also called Aranesp®. These drugs are given as shots under the skin. They can relieve symptoms of anemia and reduce the need for blood transfusions, but it usually takes at least 2 weeks for them to start working.

These anemia drugs are only used in patients who are getting chemotherapy that is not expected to cure their cancer. Some studies have shown that these drugs can cause serious side effects such as high blood pressure, heart attack, and blood clots. Other studies suggest that they may cause tumors to grow and shorten life in some people. But studies also show that patients getting chemo can get higher hemoglobin levels with less need for blood transfusions when these drugs are used, as well as gradual improvement in their anemia-related symptoms. The potential risks of these drugs must be balanced against their expected benefits.

Please call us if you would like more information about these or other drugs used in cancer treatment.

If you notice symptoms…

It’s important to watch for anemia and its symptoms throughout your treatment. Talk with a member of your cancer team if you’re having any of the symptoms described here. Be sure to mention how the symptoms affect your day-to-day life. Doing so will help you get the treatment you need when you need it.

To learn more

More information from your American Cancer Society

We have selected some related information that may also be helpful to you. Many of these materials can be read on our website, www.cancer.org. Or, you can get a free copy by calling our toll-free number, 1-800-227-2345.

More on cancer treatment

A Guide to Chemotherapy (also in Spanish)

Understanding Radiation Therapy: A Guide for Patients and Families (also in Spanish)

A Guide to Cancer Surgery (also in Spanish)

Dealing with cancer and side effects

Coping With Cancer in Everyday Life (also in Spanish)

After Diagnosis: A Guide for Patients and Families (also in Spanish)

Understanding Your Lab Test Results

Caring for the Patient With Cancer at Home: A Guide for Patients and Families (also in Spanish)

Fatigue in People With Cancer

Blood Transfusion and Donation

Nutrition for the Person With Cancer During Treatment: A Guide for Patients and Families (also in Spanish)


Your American Cancer Society also has books that you might find helpful. Call us at 1-800-227-2345 or visit our bookstore online at www.cancer.org/bookstore to find out about costs or to place an order.

National organizations and websites*

Along with the American Cancer Society, other sources of information and support include:

National Cancer Institute
Toll-free number: 1-800-422-6237 (1-800-4-CANCER)
TTY: 1-800-332-8615
Website: www.cancer.gov

    Offers accurate, up-to-date information on cancer, treatment, and coping with symptoms.

National Heart, Lung, and Blood Institute (NHLBI)
Website: www.nhlbi.nih.gov/health/health-topics/topics/anemia/

    To learn more about anemia, and how it’s diagnosed and treated

Toll-free number: 1-800-813-4673
Website: www.cancercare.org

    Offers counseling by phone, and support from others with cancer online and by phone. Cancer information and education workshops are also available.

Website: www.oncolink.org

    Online only information on cancer, treatment options, research advances, and coping with symptoms.

*Inclusion on this list does not imply endorsement by the American Cancer Society.

No matter who you are, we can help. Contact us anytime, day or night, for information and support. Call us at 1-800-227-2345 or visit www.cancer.org.


Gilreath JA, Stenehjem DD, Rodgers GM. Diagnosis and treatment of cancer-related anemia. Am J Hematol. 2014;89(2):203-212.

Hurter B, Bush NJ. Cancer-Related Anemia: Clinical Review and Management Update. Clinical Journal of Oncology Nursing. 2007;11(3):349-359.

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology. Cancer- and Chemotherapy-Induced Anemia – V.2.2015. Accessed at www.nccn.org/professionals/physician_gls/pdf/anemia.pdf on September 2, 2014.

National Heart, Lung, and Blood Institute. Explore Anemia. Accessed at www.nhlbi.nih.gov/health/health-topics/topics/anemia/ on September 2, 2014

Rosenbaum EH. Anemia causes and Treatment. Cancer Supportive Survivorship Care website. July 15, 2008. Accessed at www.cancersupportivecare.com/anemiacause.html on September 2, 2014.

Last Medical Review: 09/10/2014
Last Revised: 09/10/2014