Chemotherapy for Rhabdomyosarcoma

Chemotherapy (chemo) is the use of drugs to treat cancer. Chemo is systemic therapy, meaning that the drugs enter the bloodstream and go throughout the body to destroy cancer cells. This makes chemo useful for killing cancer cells that have spread to other parts of the body, even if they can’t be seen.

Chemo is an important part of treatment for rhabdomyosarcoma (RMS). Even if it appears that all of the cancer was removed by surgery, without chemo it is likely to come back.

After surgery, any tiny deposits of RMS that are still in the body can often be destroyed by chemo. If larger areas of tumor remain after surgery (or if surgery couldn’t be done for some reason), chemo (along with radiation) can often shrink these areas. In some cases it may shrink the tumor enough that surgery can remove the remaining tumor completely.

Chemo drugs used to treat rhabdomyosarcoma

Doctors give chemo 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, chemo is typically given once a week for the first few months, and then less often. The total length of treatment usually ranges from 6 months to a year.

Some drugs can be taken by mouth, but most are given IV (injected into a vein).

A combination of chemo drugs is used to treat patients with RMS. Which drugs are used will often depend on which risk group the patient is in.

For people in the low-risk group, the main combinations of drugs used are:

• VA: vincristine and dactinomycin (also known as actinomycin-D)
• VAC: vincristine, dactinomycin, and cyclophosphamide

For the intermediate-risk group, the most common regimens are:

• VAC: vincristine, dactinomycin, and cyclophosphamide
• VAC/VI: vincristine, dactinomycin, and cyclophosphamide, alternating with vincristine and irinotecan

Doctors are also studying whether adding the targeted drug temsirolimus to the VAC/VI regimen might help it work better.

For people in the high-risk group (which includes those with metastatic disease), the VAC regimen is the most common one used. Because these cancers can be hard to treat, doctors have also studied the use of more intense chemo that includes several other drugs (such as doxorubicin, ifosfamide, and etoposide). Another approach that has been studied is to give higher doses of chemo, sometimes followed by a stem cell transplant. But so far it's not clear that either of these approaches is any better than standard chemo, and they can cause more side effects.

Most doctors recommend that people in the high-risk group be treated in a clinical trial testing new drugs and drug combinations. It is hoped that newer drugs will help people in the high-risk group live longer.

Possible side effects

Chemo drugs can affect cells other than cancer cells, which can lead to side effects. The side effects depend on the type and doses of drugs, and the length of time they are given.

Children tend to have less severe side effects from chemo than adults and often recover from side effects more quickly. This is why doctors can often give them higher doses of chemo to kill the tumor.

General side effects: Side effects common to many chemo drugs include:

• Hair loss
• Mouth sores
• Loss of appetite
• Nausea and vomiting
• Diarrhea
• Increased chance of infections (from having too few white blood cells)
• Easy bruising or bleeding (from having too few blood platelets)
• Fatigue (from having too few red blood cells)

Most of these side effects tend to 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 report any side effects your child has so they can be managed effectively.

Side effects of certain drugs: 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, causing blood in the urine. The risk 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.
• Vincristine can damage nerves. Some patients may notice tingling and numbness (called neuropathy), particularly in the hands and feet. This often goes away or gets better once treatment is stopped, but it could last a long time in some people.
• Some drugs can also damage the ovaries or testicles, which might affect fertility (the ability to have children) later in life. Talk to the cancer care team about the risks of infertility with treatment, and ask if there are options for preserving fertility, such as sperm banking or ovarian tissue banking.
• Some chemo drugs can 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 on some of these possible long-term side effects, see What Happens After Treatment for Rhabdomyosarcoma?