HIGH-DOSE THERAPY WITH PERIPHERAL-BLOOD STEM-CELL (PBSC) SUPPORT USING AN INNOVATIVE MOBILIZATION REGIMEN IN PATIENTS WITH HIGH-RISK PRIMARY OR CHEMORESPONSIVE METASTATIC BREAST CANCERS

High-dose therapy followed by peripheral blood stem cell (PBSC) suppor t was performed in 29 patients with primary high-risk (Group I) or che moresponsive metastatic (Group II) breast cancer patients. Group I pat ients had received PBSC mobilization within 4 weeks of modified radica l mastectomy. Group II patients had to achieve minimal residual diseas e (MRD) by induction chemotherapy before being considered eligible for PBSC mobilization and high-dose therapy. An innovative FE120C regimen (5-FU 600 mg/m(2), i.v., day 1; epirubicin 120 mg/m(2), i.v., day 1; cyclophosphamide 600 mg/m(2), i.v., day 1) plus G-CSF (300 mu g/day, s ubcutaneous injection for 9 days, from day 4 post-FE120 C) was used to mobilize PBSCs. After high-dose CTCb (cyclophosphamide 6,000 mg/m(2), thiothepa 500 mg/m(2), carboplatin 800 mg/m(2), in 4 days), patients received PBSC infusion and daily C-CSF 300 mu g subcutaneous injection . There were 19 and 16 patients enrolled into Group I and Group II, re spectively. Ten of the Group II patients had achieved minimal residual disease (MRD) after induction chemotherapy. The median numbers of mob ilized total CD34 + cells for Group I and Group II patients were 27.3 (9.2 to 114.1) x 10(6)/kg and 17.1 (5.9 to 69.1) x 106/kg respectively . The median time to neutrophil recovery (ANC greater than or equal to 500/mu L) was 8 and 9 days in Group I and III respectively. The media n time to platelet recovery (greater than or equal to 50,000/mu L) was 10 and 15 days in Group I and II, respectively. No major treatment-re lated toxicities were noted. In Group I, 13 out of 19 patients (68.4%; 43-87%, 95% C.I.) remained recurrence-free with a median follow-up of 31 months (6 + to 55 + months). In Group II, 3 out of 10 patients (30 %; 7-65%, 95% C.I.) remained progression-free at 33 +, 35 +, 39 + mont hs from induction therapy. We suggest that the FE120C plus G-CSF is an effective and innovative regimen for PBSC mobilization in breast canc er patients, and high-dose CTCb therapy with PBSC support is a safe an d well-tolerated treatment modality.