Rhabdomyosarcomas can develop anywhere, but the head and neck, genital or urinary tract, and limbs are the most common locations.
Symptoms depend on where rhabdomyosarcomas develop.
Diagnosis involves an imaging test and a biopsy.
Treatment consists of surgery, chemotherapy, and sometimes radiation.
(See also Overview of Childhood Cancer.)
Rhabdomyosarcomas account for 3 to 4% of cancers in children. Two thirds of these cancers are diagnosed in children younger than 7 years of age. The cancer is slightly more common among boys than girls and is more common among whites than blacks, mainly because it is less common among black girls.
This cancer develops from cells that would normally develop into muscle cells. The cause of rhabdomyosarcoma is unknown.
Although rhabdomyosarcoma can occur almost anywhere, it tends to occur most often in the following:
Head and neck (in about 35% of cases): Most common among school-aged children
Genital or urinary tract, usually in the bladder, prostate, or vagina (in about 25% of cases): Typically occurring in infants and toddlers
Limbs (in about 20% of cases): Most common among adolescents
Trunk or other miscellaneous sites (in about 20% of cases)
Rhabdomyosarcoma can spread (metastasize) to other parts of the body. But it is usually diagnosed before the cancer has spread. About 15 to 25% of children are diagnosed after the cancer has spread. In these children, the cancer is most commonly located in the lungs. Bones, bone marrow, and the lymph nodes are other locations to which the cancer may spread.
In most children, the first evidence of the cancer is a firm lump or problems related to an organ affected by the cancer, such as the following:
Eyes: Tearing, eye pain, or a bulging eye
Nose and throat: Nasal congestion, a change in the voice, or a nasal discharge that contains mucus and pus
Genital or urinary tract: Abdominal pain, a lump in the abdomen that can be felt, difficulty urinating, and blood in the urine
Limbs: Firm lumps on the arms or legs
Limb cancers frequently spread, especially to the lungs, bone marrow, and lymph nodes. Usually, this spread does not cause symptoms.
If a lump is detected, CT or MRI is done. The diagnosis of rhabdomyosarcoma is confirmed by taking a sample from the lump and examining it under a microscope (biopsy). Sometimes the entire lump is removed.
The prognosis is based on several factors:
The prognosis is worse for children who are under 1 year of age or who are over 10 years of age.
Children are considered low risk, intermediate risk, or high risk depending on their combination of factors. More than 90% of children who are considered low risk survive, but less than 50% of children who are considered high risk survive.
(See also Cancer Treatment Principles.)
All children are treated with chemotherapy. The most common drugs used are vincristine, dactinomycin, cyclophosphamide, doxorubicin, ifosfamide, and etoposide. Topotecan and irinotecan are other drugs that may also be used.
Radiation therapy is typically used if some cancer remains after surgery or if the cancer is considered intermediate risk or high risk.