Prolonged clinical benefit with the maintenance hormone therapy in patients with metastatic breast cancer.

Abstract

e11051 Background: The maintenance hormone therapy (MHT) after cytotoxic chemotherapy is widely used by many clinicians in metastatic breast cancer patients with hormone-senstive tumors, although there are insufficient evidences in the literature to support this practice. We evaluated the efficacy of MHT and identify those who benefit most from maintenance hormone therapy. Methods: Metastatic breast cancer patients who had been treated with MHT from 2006 to 2010 in a single institute were retrospectively reviewed. Progression free survival (PFS) was a primary endpoint and predictive factors for PFS were analyzed. Results: A total of 91 patients were reviewed with a median age of 53 (range, 33-70). Aromatase inhibitors were most frequently used drugs (74.2%)for MHT. The median PFS was 12.0 months (range, 1-66). Prolonged PFS was found in patients with less previous palliative chemotherapy (one vs. two vs. more than two, 16.0 vs. 11.0 vs. 6.0 months, respectively; p=0.02), less metastatic sites (one or two vs. more than two, 15.0 vs. 6.0; p=0.04), and minimal residual disease (minimal residual disease vs. Intolerance of chemotherapy, 15.0 vs. 6.0; p=0.05). Multivariate analysis showed that HER2 overexpression status (HR 1. 89, 95% CI 1.06-3.33; p=0.03) and the minimal residual disease (HR 0.44, 95% CI 0.26-0.75; p=0.003) remained as significant variables. Conclusions: Evidence from this study showed that MHT with aromatase inhibitor siginificantly improved PFS and was well tolerated. MHT is a good therapeutic option for patients with metastatic breast cancer who have not progressed on first-line chemotherapy, especially whose hormone receptor positive, HER2-negative and minimal residual disease after cytotoxic chemotherapy.