A phase II study of two cycles of high-dose chemotherapy with autologous stem cell support in patients with metastatic breast cancer who meet eligibility criteria for a single cycle

Multi-cycle high-dose chemotherapy with autologous stem cell support (HDC-A SCS) may improve the results obtained with single-cycle HDC-ASCS in metasta tic breast cancer (MBC), However, the tolerability and efficacy of addition al cycles of HDC-ASCS in patients selected using standard eligibility crite ria for single cycle HDC-ASCS is uncertain. Twenty-nine patients with MBC a nd a CR or PR to induction chemotherapy were selected by standard instituti onal eligibility criteria for single-cycle HDC-ASCS, Cycle 1 HDC-ASCS (cycl ophosphamide 6 g/m(2); mitoxantrone 70 mg/m(2); carboplatin 800 mg/m(2)) wa s followed by a planned second cycle (etoposide 1.6 g/m(2); thiotepa 800 mg /m(2); carboplatin 800 mg/m(2) modulated by tamoxifen 120 mg/m(2)/day x 5 d ays) with a median interval of 3.2 months. CR rate was 20% after induction chemotherapy and 33% and 54% after HDC cycles I and II, respectively. Sixte en patients (55%) failed to complete HDC cycle II within 200 days because o f disease progression, toxicity, inadequate stem cell collection, insurance denials or patient choice. Median progression-free survival (PFS) for all 29 patients entered is 301 days from date of HDC cycle I and actuarial PFS at 2 years is 35%, For the 13 patients who received the two cycles of HDC-A SCS, actuarial PFS at 2 years was 54% (P = NS compared to those receiving o nly one cycle). These data show that a second cycle of full-dose intensity HDC-ASCS may increase the proportion of patients with MBC that achieve CR a nd may increase PFS, However, a large proportion of patients that complete HDC-ASCS cycle I may fail to proceed to cycle II in a timely fashion.