Metronomic Therapy for Pediatric Patients With Solid Tumors at High Risk of Recurrence

Inclusion Criteria: 1. The following solid tumors will be studied: rhabdomyosarcoma, osteosarcoma, Ewing sarcoma, other soft tissue sarcomas 2. Other solid tumors fulfilling the remainder of eligibility criteria and available historical data to determine time to tumor progression 3. Expected time to progression of \< 2 years, based on historical data 4. All patients will have completed front-line therapy 5. All patients will be in remission from their primary diagnosis 6. All patients will start metronomic therapy within 6 weeks of completion of front-line treatment 7. All patient will have recovered from previous toxicities 8. All patients or their parents/legal guardian will have signed an informed consent document 9. All institutional eligibility criteria will be meet 10. Age: Patients must be ≥ 12 months and \<31 years of age at the time of study entry 11. Patients must have had histologic verification of malignancy at original diagnosis 12. Patients must have a Lansky or Karnofsky performance status score of ≥ 50, corresponding to ECOG categories 0, 1 or 2. 13. Adequate renal function defined as: Normal serum creatinine 14. Normal liver tests (ALT/AST/total bilirubin/triglycerides/cholesterol) 15. Recovered from all surgical procedures for at least 7 days (minor procedures) or 28 days (major procedures) 16. Adequate cardiac function defined as: Shortening fraction of ≥ 27% by echocardiogram, or ejection fraction of ≥ 50% by radionuclide angiogram 17. Platelet count 100,000K/uL (transfusion independent), hemoglobin 8.0 g/dL 18. Adequate bone marrow function: Peripheral absolute neutrophil count (ANC) 1,000K/uL 19. Signed Informed Consent document and/or Assent document Exclusion Criteria: 1. Female patients who are pregnant 2. Lactating females are not eligible unless they have agreed to discontinue breastfeeding 3. Female patients of childbearing potential are not eligible unless a negative pregnancy test result has been obtained 4. Sexually active patients of reproductive potential are not eligible unless they have agreed to use an effective contraceptive method for the duration of study participation 5. Any primary central nervous system tumor 6. Any patient who has experienced relapsed or refractory disease or a second malignancy. 7. Any patient not in remission