Inclusion Criteria:

          -  Newly diagnosed participants with localized rhabdomyosarcoma (RMS).

          -  Must have either low-, intermediate-, or high-risk disease, defined as:

               -  Low-risk: Embryonal, botryoid, spindle cell tumors only (Subset 1: Stage 1, Group
                  I; Stage 1 Group I; Stage 1 Group III orbital only; Stage 2 Group I; Stage 2
                  Group II) (Subset 2: Stage 1 Group III non orbit; Stage 3 Group I, II)

               -  Intermediate-risk: Embryonal, botryoid, or spindle cell RMS Stage 2 or 3 and
                  Group III; Alveolar, undifferentiated, or anaplastic RMS: Stage 1-3, group I-I;
                  I)

               -  High-risk: Embryonal, botryoid, spindle cell, alveolar, undifferentiated, or
                  anaplastic RMS with metastatic disease at diagnosis (stage 4).

               -  Participants treated on this protocol in the low or intermediate risk arm who
                  experience disease progression prior to week 13 will transfer to the high risk
                  arm and proceed with high risk chemotherapy starting at week 1 of the protocol.

          -  Age < 22 years (eligible until 22nd birthday)

          -  Performance level corresponding to ECOG score of 0, 1, or 2. The Lansky performance
             score should be used for participants < 16 years

          -  Participant has received no prior radiotherapy or chemotherapy for rhabdomyosarcoma
             (excluding steroids) unless an emergency situation requires local tumor treatment.
             Prior biopsy, surgical resection and lymph node sampling is allowed.

          -  Initiation of chemotherapy is planned within 6 weeks (42 days) of the definitive
             biopsy or surgical resection.

          -  Adequate bone marrow function defined as:

               -  Peripheral absolute neutrophil count (ANC) ≥ 750/μL

               -  Platelet count ≥ 75,000/μL (transfusion independent)

          -  Adequate liver function defined as total bilirubin ≤ 1.5 x upper limit of normal (ULN)
             for age. Participants with biliary or hepatic primaries with bilirubin values greater
             than 1.5 x ULN may be enrolled on study if all other eligibility criteria are met.

          -  Adequate renal function defined as:

               -  Creatinine clearance or radioisotope GFR ≥ 70 mL/min/1.732 or

               -  Serum creatinine based on age and gender

               -  Participants with urinary tract obstruction by tumor must meet the renal function
                  criteria listed above AND must have unimpeded urinary flow established via
                  decompression of the obstructed portion of the urinary tract.

          -  Patients requiring emergency radiation therapy are eligible for enrollment on this
             study.

          -  Females of child-bearing potential cannot be pregnant or breast-feeding. Female
             participants ≥ 10 years of age or post-menarchal must have a negative serum or urine
             pregnancy test within 24 hours prior to beginning treatment. Female participants who
             are breast feeding must agree to stop breast feeding.

          -  Sexually active patients of childbearing potential must be willing to use effective
             contraception during therapy and for at least 1 month after treatment is completed.

          -  No evidence of active, uncontrolled infection.

          -  All participants and/or their parents or legal guardians must sign a written informed
             consent.

        Exclusion Criteria:

          -  Participants who fail to meet one or more of the inclusion criteria will be excluded.

        Inclusion Criteria for Contrast-Enhanced Ultrasound (CEUS) Sub-Study:

          -  Newly diagnosis or suspected diagnosis of previously untreated participants with
             rhabdomyosarcoma (RMS). NOTE: Patients with suspected diagnosis of RMS may enroll on
             screening part of study but must have histologic diagnosis to enroll on treatment part
             of study.

          -  Must have either intermediate-risk or high risk disease.

          -  0-21 years of age.

        Exclusion Criterial for CEUS Sub-Study:

          -  Undergoing upfront surgical resection of the primary tumor.

          -  History of allergy to Optison(TM) contrast agent or blood products.