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Chemotherapy (chemo) is the use of drugs to kill or control cancer cells. Often the drugs are given into a vein or are taken by mouth. The drugs enter the bloodstream and reach most of the body. Chemo is useful for cancers like leukemia that aren’t in one place at the time of treatment.

Doctors give chemo in cycles. A round of treatment is followed by a rest period to allow the body time to recover. Treatment cycles may last about 3 to 4 weeks.

Side effects of chemo

While chemo drugs kill cancer cells, they can damage normal cells, too. This can lead to some of the common short-term side effects, such as:

  • Hair loss
  • Mouth sores
  • Nausea and vomiting
  • Loss of appetite
  • Low white blood cell counts , which can lead to a higher risk of serious infection
  • Low blood platelets, which can lead to problems with bleeding and easy bruising
  • Low red blood cell counts, which can lead to extreme tiredness and shortness of breath with exercise

These side effects usually go away after treatment ends. And there are often ways to manage side effects during treatment. For example, drugs can be taken along with chemo to prevent or reduce nausea and vomiting. Drugs known as growth factors are sometimes given to keep blood counts higher and reduce the chance of infection.

If your white blood cell counts are very low during treatment, it increases the risk of serious infection. Your doctor may tell you to take special steps to avoid germs. You can learn more about this in Infections in People With Cancer.

You might also need transfusions of platelets or red blood cells if levels of those cells get too low.

Tumor lysis syndrome can also be a side effect of chemo. It is most common in patients who had large numbers of leukemia cells in the body before treatment. That’s why it happens most often with the first cycle of chemo. When the cells are killed, they break open and release their contents into the bloodstream. This can overwhelm the kidneys, which cannot get rid of all of these substances at once. This can lead to build up of certain minerals in the blood and even to kidney failure. Mineral build-up also can lead to problems with the heart and nervous system. Doctors work to prevent these problems by giving the patient extra fluids and certain drugs.

The section “Chemotherapy for chronic lymphocytic leukemia” in Chronic Lymphocytic Leukemia has more information on this topic.

You can learn more about chemotherapy treatments in A Guide to Chemotherapy.

Last Medical Review: 01/30/2015
Last Revised: 02/23/2016