Sarcomas are cancers that occur in the soft tissues of the body. Rhabdomyosarcoma (RMS) affects cells called rhabdomyoblasts, immature cells which go on to form the skeletal muscles of the body. Although it is the most common soft tissue cancer in children, only about 350 cases are diagnosed each year in the United States.
Rhabdomyosarcoma occurs in two distinct age groups: children five years of age and under, who are most likely to have the embryonal form of disease; and adolescent children aged 14-20, who more often have alveolar rhabdomyosarcoma. The overall five-year survival rate for rhabdomyosarcoma is 70% when detected in an early, treatable stage.
Embryonal tumors are most frequently found in the head and neck area, eye orbit, genitals and bladder. They are most common in children under the age of five. Seventy-five percent of rhabdomyoscarcomas are of this type.
Alveolar tumors are more likely to be seen in adolescents. More than one-third occur in the extremities (arms and legs), and less frequently in the head and neck, pelvis and trunk. More aggressive therapy is required to treat this form of rhabdomyosarcoma.
Symptoms depend on the location of the tumor:
Rhabdomyosarcomas can often be detected with a chest X-ray, MRI or CT scan. However, since the tumors can be similar to other cancers, a biopsy is needed to confirm the diagnosis. After the diagnosis, a bone marrow aspiration will be performed to determine if the cancer has spread to the bone marrow. A sample of marrow is extracted from the pelvic bones with a needle and examined under the microscope.
If the tumor is in a favorable location, surgery to completely remove the tumor is performed followed by chemotherapy to eliminate any lingering cancer cells. Since complete surgical removal of the tumor is not always possible, a combined approach using chemotherapy, radiation therapy and surgery may be necessary. For tumors that are difficult to reach, radiation is used with chemotherapy.