Rhabdomyosarcoma is a type of cancer that most often begins in the soft tissues of the body including tendons, muscles, nerves, fatty tissue and fibrous tissue, almost anywhere in the body. Although rhabdomyosarcoma only accounts for a small percentage of all childhood cancers, it is the most common sarcoma arising from soft tissues. It most commonly affects children and young adults between the ages of 2 and 25 and is slightly more common in males than females.
The two most common forms of rhabdomyosarcoma are called "alveolar rhabdomyosarcoma" and "embryonal rhabdomyosarcoma." These two forms appear slightly different under a pathologist’s microscope; both are highly malignant and can metastasize (spread) rapidly to other areas of the body including the bone marrow, liver, and lungs. Accurate diagnosis and staging, and prompt, carefully orchestrated therapy are particularly critical when treating rhabdomyosarcoma.
The University of Chicago Medicine Comer Children’s Hospital has a multidisciplinary team of experts with the experience and advanced resources to diagnose, analyze and treat rhabdomyosarcoma and other soft tissue sarcomas. Pediatric oncologists, radiation oncologists, surgical oncologists, pathologists, nurse specialists and others at Comer Children’s work together to strive for the best results for children with bone sarcomas.
What are the Symptoms of Rhabdomyosarcoma?
The most common symptoms of rhabdomyosarcoma are:
- A tumor or mass that can be seen or felt (may or may not be painful)
- Bleeding from the nose, vagina, rectum, or throat (may occur if the location of the tumor is in these areas)
- Tingling, numbness, pain and irregular movements (may be affected if the tumor compresses nerves in the area)
- Protrusion of the eye or a drooping eyelid (may indicate a tumor behind the eye)
These symptoms may resemble other conditions or medical problems seen in children and young adults. Always consult a physician for a diagnosis.
Rhabdomyosarcomas are challenging to diagnose and treat. Getting an accurate diagnosis is critical, but isn’t always simple. Multilevel, advanced diagnostics are necessary to detect, locate, identify and stage rhabdomyosarcoma. Once a tumor is suspected, your care team will perform imaging studies and procedures including:
- X-ray -- often used as an initial test to identify a tumor within the chest, abdomen or in a bone
- Magnetic resonance imaging (MRI) scan -- to determine the extent of the tumor
- Computed tomography (CT or CAT) scan -- to identify the location of tumors within the abdomen, chest, pelvis, or other sites
- Bone scans -- to detect rhabdomyosarcoma that may have spread to bones
- Positron emission tomography (PET) scan - to find small tumors or check if treatment is working effectively
- Ultrasound -- sometimes used in addition to CT or MRI to identify the location of a tumor within the abdomen or within a muscle.
- Biopsy - to remove a small amount of the soft tissue tumor for microscopic examination by an expert pathologist. Because rhabdomyosarcoma can also spread to the bone marrow, a sample of bone marrow is also collected as part of the staging procedures.
- Lumbar puncture/spinal tap -- to remove a small amount of cerebral spinal fluid for microsopic evaluation. This test is only needed if it appears that the rhabdomyosarcoma has extended into the brain or spinal cord.
Using extensive, specialized testing of the tissue -- often including molecular tests for genetic abnormalities within the rhabdomyosarcoma cells -- the pathologist is able to confirm the diagnosis and identify the type of sarcoma. The sarcoma team then assigns the tumor a stage number (1 - 4) and a group number (also 1 - 4). Both numbers define whether the tumor is localized to only one site or has spread to other sites, and how much (if any) has been removed by biopsy. Having the correct diagnosis and stage/group assignment is critical for optimal treatment planning.
Treatment for rhabdomyosarcomas requires several levels of therapy. Often, treatment includes surgery to remove some or all of the tumor that is visible, combined with chemotherapy and/or radiation therapy to attack microscopic tumor cells that have spread to other sites in the body. In rare cases, treatment may include a stem cell (or bone marrow) transplant. This is often done as part of a research study. Treatment plans are tailored to the needs of each patient and vary depending on the stage and group numbers for the cancer.
- Surgery -- to remove the cancer and a margin of healthy tissue surrounding it. If the tumor is in an arm or leg, it is sometimes (but rarely) necessary to remove all or part of the limb.
- Radiation therapy -- can be given before surgery to shrink the tumor or after surgery to kill any remaining cancer cells.
- Chemotherapy -- can be given to shrink the tumor and make it more accessible for surgery or radiation therapy, or both. It is also used after surgery to eliminate microscopic tumor cells that remain in the body.
- Stem cell transplant - stem cell or bone marrow transplant is sometimes recommended for patients with the highest risk disease. In this case, the use of a transplant allows even higher doses of chemotherapy to be given.
Some patients may be eligible for studies of the very newest therapies through clinical trials being conducted at Comer Children's. Parents are closely involved in deciding whether or not to enroll their child in a clinical trial. Clinical trials are only considered by the sarcoma team if they are thought to provide the best chance to cure the rhabdomyosarcoma.