Chemotherapy for rhabdomyosarcoma

All children with rhabdomyosarcoma (RMS) will get chemotherapy at some point. Even if it is thought that the cancer was completely removed by surgery, without chemotherapy it is likely to come back.

Chemotherapy (chemo) is the use of drugs to treat cancer. Chemotherapy is systemic therapy, meaning that the drugs enter the bloodstream and reach throughout the body to destroy cancer cells. This makes chemotherapy useful for killing RMS cells that have spread away from the main tumor to other parts of the body, even if they can't be seen.

Following surgery, any tiny deposits of RMS that remain can often be destroyed by chemotherapy. If larger areas of tumor remain after surgery (or if surgery couldn't be done for some reason), chemotherapy (along with radiation) can often shrink these areas. In some cases this may allow further surgery to completely remove the remaining tumor.

Drugs used to treat rhabdomyosarcoma

There are many chemotherapy drugs. Some can be taken by mouth, but most are injected into a vein. The drugs used depend to some extent on which risk group the child is in (described in the section "How is rhabdomyosarcoma staged?").

The main drugs used to treat children in the low-risk group are vincristine and dactinomycin (also known as actinomycin-D). This combination is often referred to as VA. In some cases cyclophosphamide may be added as well. This 3-drug combination is referred to as VAC.

The VAC regimen is the most common combination used for the intermediate-risk group. Irinotecan or topotecan may be added as well. Other drugs used to treat RMS include ifosfamide, etoposide, and doxorubicin.

The same drugs are also used for children in the high-risk group (which includes children with metastatic disease), but these drugs have not been shown to be as successful in this group. New drugs and drug combinations are continually being studied by the Soft Tissue Sarcoma Committee of the Children's Oncology Group and other researchers. It is hoped that they will improve the survival rate in the high-risk group.

Doctors give chemotherapy in cycles, which is usually treatment on 1 or 2 days in a row, followed by days off to give the body time to recover. For RMS, chemotherapy is typically given once a week for the first few months, and then less often. The total length of chemotherapy is usually in the range of 6 months to a year.

Possible side effects

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.

Children seem to have an advantage over adults when it comes to chemotherapy. They tend to have less severe side effects and recover from side effects more quickly. This is why doctors can often give them higher doses of chemotherapy to kill the tumor.

The side effects of chemotherapy depend on the type of drugs, the doses, and how long they are taken. Possible side effects can include:

• Hair loss
• Mouth sores
• Loss of appetite
• Nausea and vomiting
• Diarrhea
• 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)

These side effects are usually short-term and go away once treatment is finished. 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 doctor or nurse about medicines to help reduce side effects, and report any side effects your child has so they can be managed effectively.

Along with the risks above, some chemo drugs can have specific side effects (although these are relatively uncommon). For example:

Cyclophosphamide and ifosfamide can damage the bladder, which can cause blood in the urine. The chance of this happening can be lowered by giving the drugs with plenty of fluids and with a drug called mesna, which helps protect the bladder. These drugs can also damage the ovaries or testicles, which might affect fertility (the ability to have children).

Vincristine can damage nerves. Some patients may notice tingling and numbness, particularly in the hands and feet.

Recent studies have shown that children under the age of 3 years are more likely to have liver damage from chemotherapy. Doctors now use lower and very specific doses for any child younger than 3 years old.

Some chemo drugs may also increase the risk of developing a second type of cancer, usually a form of leukemia, years after the RMS is cured. But this is rare, and the importance of chemotherapy in treating RMS far outweighs this risk.

For more extensive information on chemotherapy, see the document, Understanding Chemotherapy: A Guide for Patients and Families.