What is Rhabdomyosarcoma?
Rhabdomyosarcoma is a disease in which cancer (malignant) cells begin growing in muscle tissue. Rhabdomyosarcoma is a type of a sarcoma, which means a cancer of the bone, soft tissues, or connective tissue (e.g., tendon or cartilage). Rhabdomyosarcoma begins in the soft tissues in a type of muscle called striated muscle. It can occur anywhere in the body.
Several types of sarcoma are found in children and young adults. The cancer cells must be looked at under a microscope to tell which type of sarcoma it is. Rhabdomyosarcoma is the most common type of sarcoma found in the soft tissues of children.
If your child has symptoms of a sarcoma, your child’s doctor may order x-rays and other tests. Your child’s doctor may also cut out a small piece of tissue and have it looked at under the microscope to see if there are any cancer cells. This is called a biopsy.
Your child’s chance of recovery (prognosis) and choice of treatment depend on where the cancer is located, how far it has spread, how the cells look under the microscope (histology), the type of therapy administered, how much of the cancer can be removed by surgery, and the child's age.
Stages of Childhood Rhabdomyosarcoma
Once childhood rhabdomyosarcoma is found, more tests will be done to find out if the cancer cells have spread to other parts of the body. This is called staging. Your doctor needs to know how far the cancer has spread to plan treatment.
There are several staging systems for childhood rhabdomyosarcoma. The treatment options in this summary are based on size, location, and how far and where the cancer has spread.
Cancer is found in the bones around the eye, the head and neck, near the sex organs, or near the liver, gallbladder and bile ducts.
Cancer is located in 1 area (but in none of the areas in Stage 1), is 2 inches or smaller in size, and has not spread to the lymph nodes.
Cancer is located in 1 area (but in none of the areas in Stage 1), is greater than 2 inches (5 cm) in size, and may have spread to the lymph nodes.
Cancer has spread to other areas of the body at the time of diagnosis.
Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may come back in the area where it started or in another part of the body.
How Childhood Rhabdomyosarcoma is Treated
There are treatments for all patients with childhood rhabdomyosarcoma. Three types of treatment are used, most often in combination with each other:
- Chemotherapy (using drugs to kill cancer cells)
- Radiation therapy (using high-energy x-rays or other high-energy rays to kill cancer cells)
Surgery is a common treatment for rhabdomyosarcoma. Depending on where the cancer is, your child’s doctor will take out as much of the cancer as possible, along with some of the normal tissue around it. If the cancer is too large to remove or in a place where it cannot be removed, surgery may be limited to taking out only a small piece of the cancer (biopsy). Surgery is usually followed by chemotherapy and radiation therapy. Sometimes a second surgery is done to remove cancer that remains after these treatments.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by mouth in the form of a pill, or it may be put into the body by a needle in a vein or muscle. Chemotherapy is called a systemic treatment because the drugs enter the bloodstream, travel through the body, and can kill cancer cells throughout the body.
Radiation therapy uses high-energy x-rays to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external radiation therapy) or from putting materials that produce radiation (radioisotopes) through thin plastic tubes in the area where the cancer cells are found (internal radiation therapy). Clinical trials are testing radiation given in several small doses per day (hyperfractionated radiation therapy). Clinical trials for patients with head and neck rhabdomyosarcoma are also testing intensity-modulated radiation therapy, a type of 3-dimensional radiation that uses different strengths and angles to reduce damage to healthy tissue near the tumor.
High-dose chemotherapy with stem cell transplant is being studied for rhabdomyosarcoma. This is a method of giving high doses of chemotherapy and replacing blood-forming cells destroyed by the cancer treatment. Stem cells (immature blood cells) are removed from the blood or bone marrow of the patient or a donor and are frozen and stored. After the chemotherapy is completed, the stored stem cells are thawed and given back to the patient through an infusion. These reinfused stem cells grow into (and restore) the body's blood cells. When the patient's own stem cells are used, it is called an autologous stem cell transplant.
Treatment by Stage
Treatment for childhood rhabdomyosarcoma depends on where the cancer is, how far it has spread, and what the cancer cells look like under a microscope.