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Anemia During Cancer

Cross section of blood vessel with normal amounts of red blood cells. Below it is another cross section of blood vessel showing too few red blood cells because of anemia.

Anemia is when numbers of healthy red blood cells (RBCs) in the body drop below a normal level. It can happen with cancer and during cancer treatment for many reasons. Read below to learn more about anemia during cancer and how it’s treated.

What is anemia?

RBCs are made in the bone marrow. Normally, blood is made up of about 35% to 50% RBCs. With anemia, blood has less than 35% RBCs.

RBCs carry oxygen around the body. If you have low levels of RBCs, not enough oxygen is sent to your body tissues. This may cause dizziness, weakness, or tiredness. You may have trouble doing daily tasks. You may feel cold and look pale. And you may be short of breath and have a fast heartbeat. But some people with anemia have no symptoms. This can be the case if the anemia has slowly happened over a long time.

Why anemia can happen with cancer

Anemia during cancer can have several causes. These include:

  • Treatments that damage bone marrow. These include chemotherapy and radiation therapy.

  • Some types of cancer that cause blood loss. This includes colon cancer.

  • Cancer that affects normal bone marrow function. This includes leukemia.

  • Blood loss during surgery. A lot of blood loss during cancer surgery can cause anemia.

  • Low levels of some vitamins and minerals. Not enough B vitamins or iron in your blood can cause anemia.

  • Kidney disease. This can lead to low levels of erythropoietin (EPO). This is a substance the body needs to make RBCs.

  • Wasting from cancer. Wasting means nutritional problems and weight loss. This lowers the body’s ability to make RBCs.

Testing for anemia

A blood sample is taken from your arm and then tested. Many different kinds of tests may be done on this blood. Some tests count the numbers of blood cells. Others check for substances the body uses to make RBCs, such as vitamins and iron.

Treating anemia during cancer

Treatment for anemia depends on what's causing it. It also depends on how severe your symptoms are. Your healthcare provider can tell you more about treatment options and their risks and benefits for you. Treatments include:

  • RBC transfusion. An IV tube is put into a vein in your hand or arm. RBCs from a donor are sent through the tube into your body. For a short time, this increases the number of healthy RBCs in your body. This can reverse anemia very quickly. RBC transfusions are generally safe. But there are some risks. Your healthcare provider will discuss them with you. Be sure you understand these risks. You might need to sign a consent form before getting a blood transfusion.

  • Erythropoiesis stimulating agent (ESA). This is medicine that causes the body to make more RBCs. An ESA is given as a shot. It may be given along with iron (see below). An ESA takes many weeks or even months to reverse anemia. There are certain risks with ESA treatment. Your healthcare provider will discuss them with you. Be sure you understand these risks.

  • IV (intravenous) or injection treatments. A liquid medicine with iron is given by shots or into your blood through an IV line. Several treatments may be given. IV iron might be used if you're given an ESA. IV iron usually takes 1 to 4 weeks to reverse anemia. Some vitamins may also be given as a shot (injection), such as vitamin B-12.

  • Oral supplements. You may take iron or vitamin B supplements. These come in liquid or pill form to take by mouth. Or you may have an injection. Oral supplements can take weeks or months to reverse anemia. Be sure you know exactly how and when to take them.

  • Diet changes. Eating more foods high in iron and B vitamins may help replace iron or B vitamins if you have a deficiency. Your provider can give you a list of these foods.

  • Stopping or delaying cancer treatment. Your anemia may improve if you stop or delay chemotherapy or radiation therapy for a while.

Checking your progress

During the course of your treatment, you’ll have many more blood tests done. These are to check your blood levels and your response to the treatment.

Risks and possible complications

Each treatment has its own risks. Your healthcare provider will tell you what risks apply to you. These may include:

  • Fever

  • Hives or other allergic reactions

  • Iron overload

  • High or low blood pressure

  • Nausea

  • Liver inflammation

  • Blood clots

  • Constipation

Online Medical Reviewer: Kimberly Stump-Sutliff RN MSN AOCNS
Online Medical Reviewer: Lu Cunningham RN BSN
Online Medical Reviewer: Richard LoCicero MD
Date Last Reviewed: 11/1/2019
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