Acute Lymphoblastic Leukemia: Chemotherapy

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Chemotherapy can also affect healthy cells, such as white blood cells. These cells are important in fighting infection. When white blood cells drop to very low levels, it causes a complication called neutropenia. Watch this video to learn about neutropenia and what to do if your child develops a fever during leukemia treatment.
Once your child is diagnosed with acute lymphoblastic leukemia (ALL) doctors will start your child on chemotherapy as soon as possible.

Chemotherapy uses drugs to destroy leukemic cells. These drugs are also called anticancer drugs or chemotherapeutic agents.
Generally, children tolerate chemotherapy better than adults. They can usually carry on their normal activities.

How is chemotherapy given?

There are several different ways to give chemotherapy. This depends on the type of leukemia, and on the medicine your child is taking.
The doctor gives your child chemotherapy drugs according to a schedule or timetable for each cycle or phase. You may hear your doctor refer to this as the “protocol.” The protocols are specific to the leukemia and subtype.

Child with cancer resting 
Routes of administration

There are various ways your child’s treatment team can give your child chemotherapy. These include:

  • Oral: This means that a capsule or liquid preparation is swallowed by mouth.
  • Intramuscular (IM): Chemotherapy may also be injected into a muscle. In children this is usually the thigh muscle.
  • Intrathecal (IT): The medicines are given via a lumbar puncture into your child’s spinal column. This is used to treat leukaemic cells in the cerebrospinal fluid (CSF).
  • Intravenous (IV): This is the most common way to give chemotherapy. The drugs are delivered through a needle directly into a vein. A port or central line may be used.

Central nervous system (CNS) directed chemotherapy

Leukemic cells can also cross into the fluid that surrounds the central nervous system (CNS) organs, brain and spine. This fluid is called the cerebral spinal fluid (CSF). As a result, leukemic cells can also enter your child’s CNS. When your child is diagnosed, doctors look to see whether she has leukemia cells in her spinal fluid.

  • If she has leukemia cells in her spinal fluid, your child is CNS positive. She receives CNS-direct therapy and cranial (brain) radiation.
  • If she does not have leukaemia cells in her spinal fluid, your child is CNS negative. However, leukaemia cells can still hide in the CNS even if we cannot detect them. For this reason, she receives a less intense CNS-directed therapy.

To treat leukemic cells in the CNS, doctors do a lumbar puncture. This delivers chemotherapy through the CSF.

Short-term side effects of chemotherapy

Some medicines have unwanted effects on the body. These are called side effects.  The side effects from chemotherapy drugs depend on the type of drugs, the dose of drug and your child’s reaction. Some children may not have any side effects.

Kidney problems

Chemotherapy medicines can destroy leukemic cells at a rapid rate, sometimes causing them to release substances called uric acid, potassium and phosphate into the blood. This is known as tumour lysis syndrome. High levels of uric acid can be toxic to the kidneys. If untreated, this can potentially lead to kidney failure. The kidney function can be temporarily replaced by a special machine, called dialysis.

To protect against the potential effects of tumour lysis syndrome, doctors will give your child medicines called allopurinol or rasbirucase.

Bleeding and infection

Chemotherapy medicines can also make it difficult for the bone marrow to produce normal blood cells. If this happens, your child becomes prone to infections, bleeding and developing anemia. Children who receive a more intense treatment are at a greater risk of developing these side effects. To protect against these possible risks, your child’s treatment team will provide the necessary supportive care, such as:

  • antibiotics
  • antifungal drugs
  • red blood cell and platelet transfusions


Treatment can also cause fever in children. Sometimes, this fever is associated with a decrease in white blood cells which causes a condition called neutropenia, in which the immune system is weakened. This makes a child prone to bacterial infection.
If your child develops a fever with neutropenia during treatment, she needs to go to the hospital immediately to receive intravenous antibiotics.

Side effects from steroids

As part of your child’s treatment, she takes steroids called prednisone or dexamethasone. These can cause the following side effects:

  • changes in mood or behaviour
  • bone and muscle pain
  • high blood pressure
  • high blood sugar

Other side effects during chemotherapy

While on chemotherapy, your child may experience:

  • nausea or vomiting. Medications like ondansetron, ganisetron, gravol or ativan can usually help.
  • fatigue
  • headaches
  • loss of appetite
  • sore mouth or throat (mucositis)
  • diarrhea or constipation
  • taste changes
  • pain and damage to the ends of nerves in hands, feet, or jaw (neuropathy). These side effects are often caused by the chemotherapy medicine, vincristine.
  • hearing loss
  • hair loss
  • an allergic reaction, rarely. It is usually due to the chemotherapy medicine asparaginase. To stop the reaction right away, doctors give an anti-allergy medicine.
  • Seizures, rarely
  • Blood clots (thrombosis), rarely

Other considerations during chemotherapy

Using antibiotics while on chemotherapy

Chemotherapy weakens your child’s immune system, making her prone to infection. When this happens, your child may develop pneumonia, called pneumocystis pneumonia (PCP). It is caused by the fungal organism Pneumocystis jiroveci. This fungus is normally present on our lungs, but it does not cause any disease in healthy people because their immune systems are functioning well.
To prevent your child from becoming infected, the doctor gives her an antibiotic called co-trimoxazole or Septra®. It is usually given by mouth in a tablet or liquid form, once or twice a day, three days a week throughout treatment. Your child continues to take the medicine for 3 or 6 months after she finishes treatment.

Septra® is currently the best way to protect against PCP. However, some children cannot tolerate Septra® very well. If your child experiences side effects or allergies to the medicine, she can take one of the following:

  • dapsone, which is taken by mouth
  • pentamidine, which is either inhaled or given by IV

Monitoring while your child is on chemotherapy

While your child receives chemotherapy, she has regular checkups. It is important to tell the treatment team about all of the changes or symptoms she experiences while at home. Your child’s doctor will do a physical exam and check her complete blood count (CBC).

Sometimes, your child’s blood will be taken to check that her liver and kidneys are working well. 

Tony H. Truong, MD, MPH, FRCPC

Sue Zupanec MN, NP Peds


Oussama Abla, MD