Chemotherapy for Acute Lymphocytic Leukemia

Chemotherapy (chemo) is the use of drugs to treat cancer. Most often, these drugs are injected into a vein, into a muscle, under the skin, or taken by mouth. The drugs travel through the bloodstream to reach cancer cells all over the body. This makes chemo useful for cancers such as leukemia that has spread throughout the body. Most chemo doesn’t reach the area around the brain and spinal cord well, so it may need to be injected into the cerebrospinal fluid to kill cancer cells in that area. This is called intrathecal chemo.

Doctors give chemo in cycles, with each period of treatment followed by a rest period to allow the body time to recover. Because of its potential side effects, chemo is sometimes not recommended if you are in poor health, but older age by itself should not stop someone from getting chemo if they need it and are healthy.

Chemo for acute lymphocytic leukemia (ALL) uses a combination of anti-cancer drugs. They are given in 3 phases, usually over the course of about 2 years (see Typical Treatment of Acute Lymphocytic Leukemia).

The most commonly used drugs include:

• Vincristine (Oncovin^®) or liposomal vincristine (Marqibo^®)
• Daunorubicin (daunomycin or Cerubidine^®) or doxorubicin (Adriamycin^®)
• Cytarabine (cytosine arabinoside, ara-C, or Cytosar^®)
• L-asparaginase (Elspar^®) or PEG-L-asparaginase (pegaspargase or Oncaspar^®)
• Etoposide (VP-16)
• Teniposide (Vumon^®)
• 6-mercaptopurine (6-MP or Purinethol^®)
• Methotrexate
• Cyclophosphamide (Cytoxan^®)
• Prednisone
• Dexamethasone (Decadron^®)

People typically get several of these drugs at different times during the course of treatment, but they do not get all of them.

Possible side effects

Chemo drugs attack 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 (where new blood cells are made), the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemo, which can lead to side effects.

The side effects of chemo depend on the type and dose of drugs given and the length of time they are taken. Common side effects may include:

• Hair loss
• Mouth sores
• Loss of appetite
• Nausea and vomiting
• Diarrhea
• Increased risk of infections (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)
• Numbness, tingling, or weakness in hands or feet (from nerve damage)

These side effects are usually short-term and go away once treatment is finished. There are often ways to lessen these side effects. For example, drugs can be given to help prevent or reduce nausea and vomiting. Be sure to ask your doctor or nurse about medicines to help reduce side effects, and let him or her know when you do have side effects so they can be managed effectively.

Many of the side effects of chemo are caused by low white blood cell counts. Drugs known as growth factors (G-CSF and GM-CSF, for example) may be given to speed the recovery of white blood cell counts during chemo to reduce the chance for serious infections.

Antibiotics and drugs that help prevent fungal and viral infections may be given before there are signs of infection or at the earliest sign that an infection may be developing. There are also steps that you can take to lower your risk of infection. These are discussed in Infections in People With Cancer.

Because white blood cell counts are so important during treatment, some people find it helpful to keep track of them. If you are interested in this, ask your doctor or nurse about your blood cell counts and what these numbers mean.

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.

Certain drugs might cause specific side effects. For example, cytarabine (ara-C) can cause certain problems, especially when used at high doses. These can include dryness in the eyes and effects on certain parts of the brain, which can lead to problems with coordination and balance.

Other organs that could be directly damaged by certain chemo drugs include the kidneys, liver, testicles, ovaries, brain, heart, and lungs. Doctors and nurses carefully monitor treatment to reduce the risk of these side effects as much as possible. If serious side effects occur, the chemo may have to be reduced or stopped, at least for a time.

One of the most serious side effects of ALL therapy is an increased risk of getting acute myelogenous leukemia (AML) at a later time. This occurs in a small portion of patients after they have received chemo drugs such as etoposide, teniposide, cyclophosphamide, or chlorambucil. Less often, people cured of leukemia may later develop non-Hodgkin lymphoma or other cancers. Of course, the risk of getting these second cancers must be balanced against the obvious benefit of treating a life-threatening disease such as leukemia with chemotherapy.

Tumor lysis syndrome is another possible side effect of chemo. It is most common in patients who have large numbers of leukemia cells, so it is seen most often in people getting chemo for the first time. When chemo kills these cells, they break open and release their contents into the bloodstream. This can overwhelm the kidneys, which aren’t able to get rid of all of these substances at once. Excess amounts of certain minerals may also affect the heart and nervous system. This can often be prevented by giving extra fluids during treatment and by giving certain drugs, such as allopurinol and rasburicase, which help the body get rid of these substances.