Chemotherapy for Wilms tumors

Chemotherapy (often called chemo) uses anti-cancer drugs that are given into a vein or by mouth (in pill form). These drugs enter the blood and reach all areas of the body, which makes this treatment useful for cancer that has spread or might have spread to organs beyond the kidney.

Most children with Wilms tumors will get chemotherapy at some point during their treatment. In the United States, chemo is usually given after surgery. Sometimes it may be needed before surgery to shrink a tumor to make the operation possible. In Europe, chemo is given before surgery and continued afterward. In both cases, the type and amount of chemotherapy depend on the stage and histology of the cancer.

The chemo drugs used most often to treat Wilms tumor are actinomycin D (dactinomycin) and vincristine. For tumors at more advanced stages, those with unfavorable histology, or tumors that recur after treatment, other drugs such as doxorubicin (Adriamycin), cyclophosphamide, etoposide, irinotecan, and/or carboplatin may also be used.

These drugs are injected into a vein or into a venous access device. Different drugs, doses, and lengths of treatment are used, depending on the type and stage of the Wilms tumor and the child's age. In most cases, the drugs are given once a week for at least several months. They are usually given by a nurse in the doctor's office or in the outpatient section of the hospital. In some cases, children with Wilms tumors stay in the hospital while they are getting chemotherapy, but usually this is not necessary.

Possible side effects of chemotherapy

Chemo drugs attack cells that are dividing quickly, which is why they often 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.

The side effects of chemotherapy depend on the type of drugs, the amount taken, and the length of treatment. Possible short-term side effects can include:

• Hair loss
• Mouth sores
• Loss of appetite
• Nausea and vomiting
• Diarrhea or constipation
• Increased chance of infections (from low white blood cell counts)
• Easy bruising or bleeding (from low blood platelet counts)
• Fatigue (from low red blood cell counts)

Your child's doctor and treating team will watch closely for any side effects that develop. 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 child's doctor or nurse about medicines to help reduce side effects, and let him or her know if your child has side effects so they can be managed.

Along with the effects listed above, some drugs can have specific side effects. For example:

• Vincristine can damage nerves. Some patients may notice weakness, tingling, numbness, or pain, particularly in the hands and feet.
• Doxorubicin may cause heart damage. The risk of this happening goes up as the total amount of the drug that is given goes up. Doctors try to reduce this risk as much as possible by not giving more than the recommended doses and by checking the heart with a test called an echocardiogram (an ultrasound of the heart) during treatment.
• Cyclophosphamide can damage the bladder, which can cause blood in the urine. The chance of this happening can be lowered by giving the drug with plenty of fluids and with a drug called mesna, which helps protect the bladder.

Lab tests to check for side effects of chemotherapy

Before giving chemotherapy, your child's doctor will check blood test results to check liver, kidney, and bone marrow function. If there are problems, chemotherapy may need to be delayed or the doses reduced.

The complete blood count (CBC) includes counts of white blood cells (WBCs), red blood cells (RBCs), and blood platelets. Chemotherapy can lower the numbers of these blood cells, so blood counts will be watched closely during and after chemotherapy.

Blood chemistry tests measure certain blood chemicals that tell doctors how well the liver and the kidneys are working. Some chemo drugs can damage the kidneys and liver.

Long-term side effects of chemotherapy

Possible long-term effects of treatment are one of the major challenges facing children after cancer treatment.

For example, if your child is given doxorubicin (Adriamycin), there is a chance it could damage his or her heart. Your child's doctor will carefully watch the doses used and will check your child's heart function with imaging tests.

Some chemotherapy drugs can increase the risk of developing a second type of cancer (such as leukemia) years after the Wilms tumor is cured. But this small increase in risk has to be weighed against the importance of chemotherapy in treating Wilms tumor.

See the section, “What happens after treatment for Wilms tumor?” for more on the possible long-term effects of treatment.

For more information on chemotherapy in general, see the separate American Cancer Society document, Understanding Chemotherapy: A Guide for Patients and Families.