Rhabdomyosarcoma

Children do not typically have systemic symptoms such as fever, night sweats, or weight loss. Usually, children present with a firm, palpable mass or with organ dysfunction due to impingement of the organ by the cancer.

Orbital and nasopharyngeal cancers may cause tearing, eye pain, strabismus, visual disturbance, or proptosis (1).

Nasopharyngeal cavity cancers may cause nasal congestion, a change in voice, or mucopurulent discharge.

Genitourinary cancers cause abdominal pain, a palpable abdominal mass, difficulty urinating, and hematuria. Vaginal tumors can manifest with mucosanguineous discharge with a polypoid mass protruding from the vagina. Paratesticular tumors often present as painless scrotal masses.

Scapular Rhabdomyosarcoma

Image

This photo shows rhabdomyosarcoma presenting as a scapular mass with pain and reduced movement.

GIRAND, BSIP/SCIENCE PHOTO LIBRARY

Extremity cancers appear as firm, indiscrete masses anywhere on the arms or legs.

For all rhabdomyosarcomas, regional lymph node spread occurs frequently (2). Metastases in the lungs, bone marrow, and lymph nodes can occur but usually do not cause symptoms.

• MRI or CT depending on location

• Excision or biopsy

• Additional imaging to evaluate for metastasis

• Tumor molecular profiling

Masses are evaluated by MRI, but CT is sometimes used for localized disease depending on location (1). Diagnosis of rhabdomyosarcoma is confirmed by excision (when possible) or biopsy of the mass.

The standard metastatic evaluation includes chest CT, positron emission tomography (PET)–CT, or PET-MRI (1, 2). Lumbar puncture for patients with parameningeal disease with intracranial/meningeal involvement, bone marrow evaluation (for certain high-risk groups only), or fluorodeoxyglucose (FDG)-PET scan is sometimes performed.

Tumor molecular profiling with genetics (FOXO1 fusion status and often other genetic markers) is performed for risk stratification.

• Chemotherapy

• Sometimes surgery

• Sometimes radiation therapy for residual bulk or microscopic disease

The treatment approach for rhabdomyosarcoma is multimodal, consisting of chemotherapy in combination with surgery, radiation therapy, or both.

Children in all risk categories are treated with chemotherapy; the most commonly used are vincristine, actinomycin D (dactinomycin), cyclophosphamide, doxorubicin, ifosfamide, and etoposide (1). Topotecan and irinotecan also have activity against this cancer type as well (2, 3). Maintenance chemotherapy with vinorelbine plus low-dose oral cyclophosphamide has also been shown to be beneficial in patients with high-risk, localized rhabdomyosarcoma who achieve complete remission after standard therapy with ifosfamide, vincristine, and actinomycin D (4).

Complete excision of the primary cancer is recommended when it can be performed safely without significant deformity or loss of function (1). Because the cancer is responsive to chemotherapy and radiation therapy, aggressive resection is discouraged if it may result in organ damage or dysfunction.

Indication for radiation therapy depends on clinical group, FOXO1 fusion status, and margin status. Radiation therapy is generally recommended for children with residual bulk disease or microscopic residual tumor after surgery, for children with intermediate-risk or high-risk disease, and for all patients with FOXO1 fusion (1).

Prognosis is based on:

• FOXO1 fusion status

• Cancer location (better with nonparameningeal head/neck and nonbladder/nonprostate genitourinary cancers)

• Completeness of resection

• Presence of metastasis

• Age

Combinations of these prognostic factors place children in a low-risk, intermediate-risk, or high-risk category. A complex risk stratification system exists (see the National Cancer Institute's stage information for childhood rhabdomyosarcoma). FOXO1 fusion status has replaced histologic subtype as the primary molecular classifier in both Children's Oncology Group (COG) and European Paediatric Soft Tissue Sarcoma Study Group (EpSSG) risk stratification systems (1, 2).

Treatment intensifies with each risk category, and overall 5-year survival ranges from approximately 90% in children with low-risk disease to approximately 20% in children with high-risk disease (3).

The following English-language resource may be useful. Please note that The Manual is not responsible for the content of this resource.

1. National Cancer Institute: Childhood Rhabdomyosarcoma Treatment (PDQ)-Health Professional Version