A Phase II Trial for Patients With Inflammatory (Stage IIIB) and Responsive Metastatic Stage IV Breast Cancer Using Busulfan, Melphalan and Thiotepa Followed by Autologous or Syngeneic PBSC Rescue and 12 Weeks of Post-Engraftment Immunotherapy With Low-Dose IL-2 and GM-CSF

PRIMARY OBJECTIVES: I. To determine the event-free survival and survival of patients treated for inflammatory (Stage IIIb) and responsive stage IV breast cancer with BUMELTT and PBSC support and low dose immunotherapy with IL2 and GM-CSF. SECONDARY OBJECTIVES: II. To determine the toxicity of a combination of low-dose IL-2 and GM-CSF in patients following HDC with BUMELTT and PBSC support. OUTLINE: PREPARATIVE REGIMEN: Patients receive busulfan orally (PO) once every 6 hours on days -8, -7, and -6; melphalan IV over 30 minutes on days -5 and -4; and thiotepa IV over 2 hours on days -3 and -2. TRANSPLANTATION: Patients undergo autologous peripheral blood stem cell infusion on day 0. POST-TRANSPLANT THERAPY: All patients receive tamoxifen citrate* PO once daily beginning prior to aldesleukin (IL-2) and sargramostim (GM-CSF) therapy and continuing for 5 years or until relapse (estrogen receptor [ER]- or progesterone receptor [PR]-positive patients) OR until completion of IL-2/GM-CSF therapy (ER-negative or PR-negative patients). Eligible patients receive IL-2 subcutaneously (SC) daily and GM-CSF SC 3 times weekly for 12 weeks beginning 30-100 days after transplantation. Patients may receive radiotherapy after completion of IL-2/GM-CSF treatment if no prior radiotherapy was given before transplantation. *Stage IV patients not receiving IL-2/GM-CSF therapy who received tamoxifen citrate as part of adjuvant therapy and subsequently failed, receive oral anastrozole once daily for 5 years or until progression instead of tamoxifen. [*For postmenopausal patients, the choice and duration of hormonal therapy given in addition to or an alternative to tamoxifen therapy will be at the physician's discretion] Patients are followed up every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.