Survival of metastatic breast carcinoma patients over a 20-year period: a retrospective analysis based on individual patient data from six consecutive studies

Abstract

Background: The expectation of improvement in patient survival with administration of new chemotherapy agents for metastatic breast carcinoma (MBC) is not consistently supported by data from clinical trials, which are often underpowered and have not detected moderate survival advantage. The aim of this study was to evaluate the impact of new agents on prognosis of MBC patients enrolled in clinical trials of first-line chemotherapy.

Methods: Between 1983 and 2001, 640 MBC patients were entered into 6 consecutive trials; the present analysis was limited to patients. The date of diagnosis of metastatic breast disease was used to define 5 arbitrarily chosen 3-year time cohorts, 1983-1986, 1987-1989, 1992-1994, 1995-1997, and 1998-2001. Multivariate proportion of hazard (PH) models were used to evaluate changes in overall survival (OS) and progression-free survival (PFS) over time and to detect changes associated with the use of taxanes, while adjusting for differences in baseline factors among 5 cohorts.

Results: Patient characteristics were evenly distributed across the 5 cohorts. Median OS was 18 months, 17.2 months, 19.2 months, 26.1 months, and 23.6 months, respectively, in cohorts 1983-1986, 1987-1989, 1992-1994, 1995-1997, 1998-2001 (P < 0.0001). Age, performance status, relapse-free survival, type of adjuvant treatment, metastatic site, and taxane first-line chemotherapy were all associated with survival. These data failed to provide an indication of temporal trend and suggested a reduction in hazard of death in two cohorts (1995-1997 and 1998-2001) where taxane was added to first-line chemotherapy.

Conclusions: The analysis provided evidence of improvement in prognosis of MBC patients that was associated with use of modern chemotherapeutic agents independent of time.