High dose chemotherapy and autologous bone marrow or stem cell transplantation versus conventional chemotherapy for women with metastatic breast cancer.

BACKGROUND: There is a hypothesis that high dose chemotherapy with autologous bone marrow or stem cell transplantation (autograft) may improve survival for women with metastatic breast cancer.
OBJECTIVES: To compare the effectiveness of high dose chemotherapy and autologous bone marrow or stem cell transplantation with conventional chemotherapy for women with metastatic breast cancer. SEARCH STRATEGY: We used the Cochrane Breast Cancer Group search strategy, adding these terms: bone marrow transplantation, stem cell transplantation, autologous stem cell support. The following databases were searched: MEDLINE (until August 2002), EMBASE (until July 2002), ASCO (American Society of Clinical Oncology) (1995-2002) and the COCHRANE LIBRARY (Issue 3 2002). We searched the Cochrane Breast Cancer Group database and cooperative research groups' websites for unpublished trials. SELECTION CRITERIA: Randomised controlled trials comparing the effectiveness of high dose chemotherapy and autograft with conventional chemotherapy for women with metastatic breast cancer. Studies included one or more of the following outcomes: treatment related mortality, overall or progression-free survival at 1, 2, 3, 5 or 7 years, morbidity, quality of life measures, time to tumour progression, overall survival time. DATA COLLECTION AND ANALYSIS: Five randomised controlled trials met the inclusion criteria. Two independent reviewers extracted data. MAIN
RESULTS: In total 382 women were randomised to receive high dose chemotherapy with autograft and 358 were randomised to receive conventional treatment. There were ten treatment related deaths among the high dose group and none reported in the control (conventional dose) group (RR 5.70, 95%CI (1.30, 25)). There was no statistically significant difference in overall survival between the high dose and control groups (at one year: RR 0.99, 95% CI (0.91, 1.08); three years: RR 1.16 95% CI (0.90, 1.51); five years: RR 1.28, 95% CI (0.72, 2.27)). At one and two years of follow up, a statistically significant difference in progression free survival was reported, favouring the high dose group (one year: RR 1.81, 95% CI (1.39,2.34); two years: RR 1.96, 95% CI (1.32, 2.90 ). However this difference was not evident at three or five years (three years: RR 1.44, 95% CI (0.85, 2.44); five years: RR 1.21, 95% CI (0.40, 3.69). Toxicity was more severe in the high dose group. None of the trials has completed follow up and further data are awaited. REVIEWER'S
CONCLUSIONS: Although there is evidence that high dose chemotherapy and autograft improves progression free survival at one and two years' follow up compared to conventional chemotherapy, there is no evidence of benefit in overall survival.