The main purpose of this study is to see if using proton beam radiation therapy instead of photon beam radiation therapy can reduce side effects from radiation treatment for rhabdomyosarcoma. Photon beam radiation is the standard type of radiation for treating most rhabdomyosarcoma and many other types of cancer. Photon beam radiation enters the body and passes through healthy tissue, encounters the tumor, then leaves the body through healthy tissue. A beam of proton radiation enters the body and passes through healthy tissue, encounters tumor, but then stops. This means that less healthy tissue is affected by proton beam radiation than by photon beam radiation.

• A special device is made for each participant to help them hold still during the treatment. This may be in the form of a mask or a custom made foam cradle depending on the area to be treated.
• Radiation treatments will be given once per day, 5 days a week for a total of 4 to 6 weeks, depending upon how much total dose the tumor requires.
• Participants will be seen once per week by their radiation doctor to monitor health and record any side effects from treatment.
• After the radiation treatments are completed, participants will be required to undergo further tests and evaluations for several years following treatment.

Inclusion Criteria:

• Patients with biopsy proven newly diagnosed rhabdomyosarcoma.
• Patients less than or equal to 30 years of age.
• Patients must be treated with a standardly accepted chemotherapy regimen.
• May not have metastatic disease unless aged 2-10 with embryonal histology.
• Must be willing to receive follow-up care for a minimum of five years after treatment at MGH and annual visits unless it is too difficult to return to MGH for follow-up care. In that event, they must be willing to have their outside medical information released to us to track the results.
• Timing of radiation must be according to the IRB protocol upon which the patient is treated within either 35 days of last chemotherapy or surgery.

Exclusion Criteria:

• Life expectancy of less than 2 years.
• Co-morbidities that would make the use of radiation too toxic to deliver safely, such as serious local injury or collagen vascular disease.
• Patients who are pregnant
• Previous treatment with radiation therapy.

All adverse events, both serious and non-serious, and deaths were collected from the initiation of study intervention, during treatment, and annually for at least 5 years from the start of radiation treatment.

Acute toxicity was scored at weekly status check visits by the radiation oncology nurse or doctor. In addition, acute toxicity was scored at least one time within the 3 months following completion of radiation therapy. Late toxicity were scored on a yearly follow-up basis for at least five years. Adverse events were monitored through study completion. Toxicities are graded according to the Common Terminology Criteria for Adverse Events (CTCAE), Version 3.0.