Chemotherapy for metastatic breast cancer. Comparison of clinical practice and cost of drugs in two cohorts of patients: 1994-1998 and 2003-2006.

Although new chemotherapeutic drugs for metastatic breast cancer (MBC) have been approved over the past decade, it is unclear whether this has changed the overall outcome of patients. This study assessed the clinical and economic impacts of these drugs. We retrospectively studied MBC patients receiving chemotherapy in our institution over two time periods, 1994-1998 and 2003-2006. Patient characteristics and outcomes, and treatment characteristics and costs (€, 2008) were compared. Three hundred and one patients were identified, 149 patients in the first cohort and 152 in second one. The median number of lines of chemotherapy was similar in the two cohorts (three lines). The median costs of chemotherapy per patient nearly doubled over time, from 6,272 € in the 1994-1998 cohort to 13,035 € in the 2003-2006 cohort (P < 0.001). No survival difference was observed between the two groups, with a 3-year survival rate estimated to 41% in the 1994-1998 cohort and 44% in the 2003-2006 cohort (P = 0.52). In multivariate analysis, prognostic factors associated with longer overall survival were single metastatic site (HR 0.48; P < 10⁻³), bone metastases (HR = 0.67; P = 0.007) and positive hormone receptors (HR 0.56; P = 0.0002). New chemotherapeutic agents induced a significant cost increase over time. The limited size and heterogeneity of our cohort do not allow any conclusion concerning their impact on survival.