Chemotherapy for Chronic Myeloid Leukemia

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 or TKIs) can be considered chemo, but here chemo is used to mean treatment with conventional cytotoxic drugs that mainly kill cells that are growing and dividing rapidly.

Chemo was once one of the main treatments for patients with chronic myeloid leukemia (CML), but it is used much less often now that TKIs like imatinib (Gleevec^®) are available. Now, chemo may be used to treat CML when the TKIs have stopped working. It is also used as part of the treatment during a stem cell transplant.

The chemo 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^®).

Omacetaxine (Synribo^®) is a chemo drug that was approved to treat CML that is resistant to some of the TKIs now in use. It can help some patients whose CML has developed the T315I mutation that keeps most TKIs from working (discussed in the section about targeted therapy).

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
• Low white blood cell counts (leukopenia), which increases the risk of serious infection
• Low blood platelet counts (thrombocytopenia), which can lead to easy bruising or bleeding
• Low red blood cell counts (anemia), which can lead to feeling tired and weak

Still, different drugs can have different side effects. For example, vincristine can cause nerve damage (neuropathy) leading to numbness, tingling, or even pain or weakness 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 time 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.

If your white blood cell count gets very low after treatment with chemo, drugs known as growth factors, G-CSF (Neupogen^®) and GM-CSF (Leukine^®), for example, may be given to increase the white blood cell counts and reduce the chance of infection.

For information on infections and how to avoid them, see Infections in People With Cancer.

If your platelet counts are low, you may be given drugs or platelet transfusions to help protect against bleeding. Likewise, if low red blood cell counts are causing problems (like shortness of breath and/or weakness), you may be treated with red blood cell transfusions.

More information about chemotherapy can be found in the chemotherapy section of our website.