Diagnosing Rhabdomyosarcoma
Many tests and procedures are needed on children who have suspected signs and symptoms of RMS. The exact combination of tests will help to determine if and where cancer cells are present in the body. Your child’s oncologist will use some of the following procedures to identify the extent of the disease:
- Examination of the site of the tumor: The tumor site can be examined by imaging studies, such as an MRI, to determine the size and exact location of the tumor, as well as any potential spread through the body.
- Biopsy: The only way to determine the exact tumor type is by removing a piece of the tumor and having a pathologist examine it under the microscope. This is known as a biopsy. In some cases, the primary tumor can be completely removed at the same time. Under the microscope, RMS can look similar to several other types of children’s cancers such as neuroblastoma, Ewing sarcoma, and lymphoma. It is very important to be absolutely sure about the cancer cell type before deciding on a treatment plan.
- Examination of the body for signs the tumor has spread: The common sites of metastasis (spread of the cancer cells) include the lungs, bone marrow and bones. Some of the common tests that may be used for evaluation include:
Survival
It is now possible to cure nearly 3 of every 4 children with rhabdomyosarcoma. Based on patient and tumor characteristics, prognostic factors are designated as more or less “favorable”. These factors are also used to determine the best choice of therapy. Although the “unfavorable” forms of cancer require more intensive treatment than “favorable,” all RMS patients need to be treated with chemotherapy. Surgery and/or radiation therapy are inevitably part of the treatment regimen.
The most important prognostic factors include:
- Primary tumor site: Some tumor sites are defined as favorable. These include tumors that arise around the orbit, superficial sites in the head and neck, the vagina, and around the testicles. All other sites, including parameningeal, extremity, bladder and prostate gland are classified as unfavorable.
- Histology subtype: Embryonal histology tumors have a more favorable outcome.
- Age: Patients under one and over 10 years of age have a somewhat less favorable prognosis.
- Presence of distant metastasis: Patients whose tumors have metastasized (spread to other areas) at the time of diagnosis have a less favorable prognosis.
Causes of Rhabdomyosarcoma
Researchers currently do not know what causes rhabdomyosarcoma. In most cases, there are no clear predisposing risk factors for the development of RMS. However, it has been associated with some inherited diseases including:
- Neurofibromatosis type 1
- Beckwith-Wiedemann syndrome
- Li-Fraumeni syndrome
- Cardio-facio-cutaneous syndrome
- Costello syndrome
Children with these conditions are at higher risk for rhabdomyosarcoma, but these account for only a small fraction of cases.
