Double dose-intensive chemotherapy with autologous stem-cell support for metastatic breast cancer: no improvement in progression-free survival by the sequence of high-dose melphalan followed by cyclophosphamide, thiotepa, and carboplatin.

PURPOSE

Twenty-one percent of responding metastatic breast cancer patients remain progression-free a median 50 months following one intensification cycle of cyclophosphamide (6,000 mg/m2), thiotepa (500 mg/ m2), and carboplatin (800 mg/m2) (CTCb) with autologous bone marrow transplantation (ABMT). This trial studied whether the sequence of high-dose melphalan followed by CTCb resulted in improved disease response and duration.

METHODS

Women with at least partial responses (PRS) to induction received melphalan (140 or 180 mg/ m2) with peripheral-blood progenitor cell (PBPC) and granulocyte colony-stimulating factor (G-CSF) support. They were monitored as outpatients. After recovery, patients were hospitalized for CTCb with marrow, PBPC, and G-CSF support.

RESULTS

Data on 67 women, at a median of 25 months from CTCb, were examined. After melphalan, 49 (73%) required admission for fever (89%), mucositis (35%), or infection (15%) (median stay, 8 days). All received CTCb. For the first 33 patients, the median days from start of melphalan to CTCb was 24. After liver toxicity (one death from venoocclusive disease [VOD]) developed in 11 patients during CTCb, the interval between intensifications was increased to 35 days without incident. Twenty-three patients (34%) are progression-free a median of 16 months post-CTCb. The median progression-free survival (PFS) and survival times for the whole group are estimated at 11 and 20 months, respectively.

CONCLUSION

Treatment with this sequence of high-dose melphalan followed by CTCb has not resulted in superior PFS to date, when compared with single-intensification CTCb. This report discusses factors related to patient selection, the role of induced drug resistance, and the schedule of administration of alkylating agenting that may adversely influence outcome.