Chemotherapy (chemo) is the use of anti-cancer drugs that are injected into a vein or taken by mouth. These drugs enter the bloodstream and reach all areas of the body, making this type of treatment useful for cancers such as leukemia that spread throughout the body. Any drug used to treat cancer (including tyrosine kinase inhibitors) can be considered chemotherapy, but in this document the term chemotherapy is used to mean conventional cytotoxic chemotherapy with drugs that mainly kill cells that are growing and dividing rapidly.
Chemotherapy was once one of the main treatments for patients with chronic myeloid leukemia (CML), but it is used much less often now that drugs like imatinib are available. Now, chemotherapy may be used to treat CML when the tyrosine kinase inhibitors have stopped working. It is also used as part of the treatment during a stem cell transplant.
The chemotherapy drug hydroxyurea (Hydrea®) is taken as a pill, and can help lower very high white blood cell counts and shrink an enlarged spleen. Other drugs sometimes used include cytarabine (Ara-C), busulfan, cyclophosphamide (Cytoxan®), and vincristine (Oncovin®).
Side effects of chemotherapy
Chemotherapy drugs work by attacking cells that are dividing quickly, which is why they work against cancer cells. But other cells in the body, such as those in the bone marrow, the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemotherapy, which can lead to side effects.
Possible side effects depend on the type and dose of drugs given and the length of time they are taken. Some common side effects of chemotherapy include:
- Hair loss
- Mouth sores
- Loss of appetite
- Nausea and vomiting
- Increased risk of infection (due to low white blood cell counts)
- Easy bruising or bleeding (due to low blood platelet counts)
- Fatigue (due to low red blood cell counts)
Still, different drugs can have different side effects. For example, vincristine can cause nerve damage (neuropathy) leading to numbness, tingling, or even pain in the hands or feet. Lung damage from busulfan is rare, but can be severe. Before starting treatment, speak with your health care team about the drugs you will receive and their possible side effects. Most side effects last a short while and go away once treatment is finished, but some can be permanent.
While getting treatment, be sure to tell your cancer care team about any side effects you have because there may be ways to lessen them. For example, drugs can be given to prevent or reduce nausea and vomiting.
Drugs known as growth factors (G-CSF (Neupogen) and GM-CSF (Leukine), for example) are sometimes given to increase the white blood cell counts and thus reduce the chance of infection. If your white blood counts are very low during treatment, you can also reduce your risk of infection by avoiding exposure to germs. During this time, your doctor may advise that you:
- Wash your hands often.
- Avoid fresh, uncooked fruits and vegetables and other foods that might carry germs.
- Avoid fresh flowers and plants because they may carry mold.
- Make sure other people wash their hands when they come in contact with you.
- Avoid large crowds and people who are sick (wearing a surgical mask offers some protection in these situations).
You may also be given antibiotics before there are signs of infection or at the earliest sign that an infection may be developing.
If your platelet counts are low, you may be given drugs or platelet transfusions to help protect against bleeding. Likewise, shortness of breath and extreme fatigue caused by low red blood cell counts may be treated with drugs or with red blood cell transfusions.
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