Intensity-Modulated Radiation Therapy, Etoposide, and Cyclophosphamide Followed By Donor Stem Cell Transplant in Treating Patients With Relapsed or Refractory Acute Lymphoblastic Leukemia or Acute Myeloid Leukemia

RATIONALE: Giving intensity modulated radiation therapy (IMRT) and chemotherapy, such as etoposide and cyclophosphamide, before a donor stem cell transplant helps stop the growth of cancer cells. It also helps stop the patient's immune system from rejecting the donor's stem cells. When the healthy stem cells from a donor are infused into the patient they may help the patient's bone marrow make stem cells, red blood cells, white blood cells, and platelets. Sometimes the transplanted cells from a donor can make an immune response against the body's normal cells. Giving IMRT together with chemotherapy before transplant may stop this from happening. PURPOSE: This phase I/II trial is studying the side effects and best dose of intensity-modulated radiation therapy (IMRT) when given together with etoposide and cyclophosphamide followed by donor stem cell transplant and to see how well they work in treating patients with relapsed or refractory acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML).

OBJECTIVES: I. To establish the maximum tolerated dose \[MTD\] of large field image-guided IMRT, using helical tomotherapy when given in combination with intravenous cyclophosphamide and VP-16 as a preparative regimen for allogeneic hematopoietic stem cell transplantation (HSCT) from an human leukocyte antigen (HLA)-identical sibling or unrelated donor in patients with ALL or AML with induction failure or in relapse. (Phase I) II. To describe the toxicity at each dose level standard. (Phase I) III. To collect data on the radiation dose to normal organs and bone marrow using tomotherapy targeted total-body irradiation (TBI). (Phase I) IV. To estimate the overall survival probability, disease free survival probability and relapse rate associated with this regimen. (Phase II) V. To characterize the treatment related mortality and toxicity profile (early/late) associated with this regimen. (Phase II) VI. To descriptively compare the outcomes of patients treated on this protocol to a comparable patient population conditioned with whole body radiation. (Phase II) OUTLINE: This is a phase I, dose-escalation study of intensity-modulated radiation therapy (IMRT) followed by a phase II study. PREPARATIVE REGIMEN: Patients undergo IMRT using helical tomotherapy once or twice daily on days -10 to -6 or -10 to -7. Patients also receive etoposide intravenously (IV) on day -6 or -5 and cyclophosphamide IV on day -4 or -3. TRANSPLANTATION: Patients undergo allogeneic peripheral blood stem cell or bone marrow transplantation on day -1 or day 0. After completion of study treatment, patients are followed up periodically for up to 2 years.