Evolutionary Therapy for Rhabdomyosarcoma

Inclusion Criteria: * Participants must have a new histologic diagnosis of rhabdomyosarcoma * Participants must have FISH, PCR or other molecular confirmation of PAX/FOXO1 fusion per institutional standards * Participants must have sufficient tissue (up to 10 unstained FFPE) for correlative testing * All participants must have distant metastatic disease; either biopsy positive or PET avid extranodal or distant nodal lesions determined by the investigator to be metastatic disease. Patients with a single distant metastatic site that has been excised prior to study entry are eligible * No prior systemic chemotherapy * Participants enrolled to Arm B, maintenance, must be able to take oral cyclophosphamide. Note: enteral administration of cyclophosphamide is allowable. * Males and females of reproductive potential may not participate unless they have agreed to the use of, at minimum, two methods of contraception during and after treatment or abstinence. * Women of childbearing potential should adhere to contraception for a period of 4 months after completion of systematic chemotherapy administration * Men who are sexually active with women of child bearing potential should adhere to contraception for a period of 4 months after completion of systematic chemotherapy administration * All patients and/or their parents or legal guardians must have the ability to understand and the willingness to sign a written informed consent or assent document. Exclusion Criteria: * Participants with regional lymph nodes as the only site of disease are not eligible. Distant nodal sites alone are eligible * Participants who are receiving any other investigational agents for rhabdomyosarcoma are ineligible * Participants must not be receiving any additional medicines being given for the specific purpose of treating cancer. Alternative medications including, but not limited to cannabis based products would not be a reason for exclusion * Participants are ineligible if they have uncontrolled intercurrent illness including, but not limited to: * ongoing or active infection not expected to resolve with current antibiotic plan * cardiac arrhythmia * psychiatric illness/social situations that would limit compliance with study requirements * Patients who are pregnant or breastfeeding are not eligible because there is no available information regarding human fetal or teratogenic toxicities. Females of childbearing potential must have a negative serum or urine pregnancy test within 24 hours of starting protocol therapy. * Participants who are considered unable to comply with the safety monitoring requirements of the study are not eligible