Background: We retrospectively evaluated the efficacy of first-line epirubicin and docetaxel in patients with metastatic, hormonal receptor (HR)-positive, and human epidermal growth factor receptor-2-negative breast cancer. A subgroup analysis evaluated the predictive value of immunohistochemistry-defined luminal subtype.
Methods: We included patients with at least one visceral and measurable site of metastatic disease. Patients were grouped as luminal A (HR(+) and Ki67<13%) or luminal B (HR(+) and Ki67>13%).
Results: Forty-four patients were entered and prognostic variables were similar between the subgroups. Luminal B patients achieved higher objective response rate than luminal A (69% versus 19%; P = 0.001), longer time to progression (12.2 months versus 8.6 months; P = 0.039), and longer overall survival (24.6 months versus 19.5 months; P = 0.041). The multivariate analysis confirmed the predictive value of luminal B subtype for longer time to progression.
Conclusions: Identification by Ki67 labelling index of human epidermal growth factor receptor-2-negative luminal A could predict a substantial benefit from systemic chemotherapy. Endocrine therapy would be the most appropriate therapy for luminal A tumours.