Approved by the Cancer.Net Editorial Board, 06/2018

Anemia is an abnormally low level of red blood cells. It occurs when:

  • The body does not make enough red blood cells.

  • The body loses blood.

  • The body destroys red blood cells.

It is common for people with cancer to have anemia. This is especially true for those receiving chemotherapy. Most people with anemia feel tired or weak. People with this symptom may have a harder time coping with the physical and emotional demands of treatment.

About red blood cells

Red blood cells contain hemoglobin. Hemoglobin is an iron protein that carries oxygen to all body parts. When red blood cell levels are too low, the body parts do not get enough oxygen. As a result, they cannot work properly.

Red blood cells are made in bone marrow. Bone marrow is the soft, spongy tissue found inside larger bones. A hormone called erythropoietin tells the body when to make more red blood cells. This hormone is made in the kidneys. Therefore, damage to bone marrow or the kidneys can cause anemia.

Signs and symptoms

Managing symptoms, which can include anemia, is an important part of cancer care and treatment. This is called palliative care or supportive care. Talk with your health care team about any symptoms you or the person you are caring for experience.

People with anemia may have some of these symptoms:

Causes of anemia

The following factors can cause anemia:

  • Chemotherapy. Chemotherapy damages bone marrow. But this is usually temporary, and anemia usually improves a few months after chemotherapy ends. Also, chemotherapy with platinum drugs may harm the kidneys. These drugs include cisplatin (Platinol) and carboplatin (Paraplatin).

  • Radiation therapy. Certain types of radiation therapy damage bone marrow:

    • Radiation therapy to large areas of the body

    • Radiation therapy to bones in the pelvis, legs, chest, or abdomen

  • Certain types of cancer. Leukemia, lymphoma, and multiple myeloma damage bone marrow. Also, cancers that spread to the bone or bone marrow may crowd out normal red blood cells.

  • Nausea, vomiting, and loss of appetite. Nausea and vomiting and loss of appetite may cause a lack of nutrients. The body needs these nutrients to make red blood cells. These include iron, vitamin B12, and folic acid.

  • Excessive bleeding. Sometimes, red blood cells are lost faster than the body is able to replace them. This may happen after surgery or if a tumor causes internal bleeding.

Diagnosing anemia

Doctors use a blood test to diagnose anemia. It is called a complete blood count test. The test results include the number of red blood cells. A red blood cell count is measured in several ways. The 2 most common measurements are hemoglobin and hematocrit. The hematocrit is the percentage of your blood that is made up of red blood cells.

People with specific types of cancer types or who are receiving certain cancer treatments may have regular blood tests. These tests look for anemia and other blood-related problems. If test results show that you have anemia, you may need additional tests to find the cause.

Treating anemia

Doctors treat anemia based on the cause and symptoms. Here are some examples:

  • Blood transfusion. If anemia causes symptoms, you may need a transfusion of red blood cells.

  • Medications. If chemotherapy causes anemia, doctors may prescribe erythropoiesis-stimulating agents. These include epoetin alfa (Epogen, Eprex, Procrit) or darbepoetin alfa (Aranesp). These drugs are forms of erythropoietin grown in the laboratory. They work by telling bone marrow to make more red blood cells.

    Epoetin and darbepoetin are injected into the body in regular intervals. They can take up to 4 weeks to start working. These drugs are also associated with serious health risks, such as an increased risk of blood clots.

  • Vitamin or mineral supplements. If a lack of nutrients causes anemia, doctors may prescribe supplements. These include iron, folic acid, or vitamin B12. These supplements are usually pills taken by mouth. Occasionally, you may receive a vitamin B12 injection. This may help the body absorb the vitamin.

    Also, consider eating foods high in iron or folic acid.

    Foods high in iron include:

    • Red Meat

    • Beans (legumes)

    • Dried apricots

    • Almonds

    • Brocolli

    • Enriched breads and cereal

    Foods high in folic acid include:

    • Asparagus

    • Broccoli

    • Spinach

    • Lima beans

    • Enriched breads and cereals

Related Resources

ASCO Answers Fact Sheet: Anemia (PDF)

When to Call the Doctor During Cancer Treatment

More Information

National Cancer Institute: Anemia (PDF)