Combination treatment with aromatase inhibitor and capecitabine as first- or second-line treatment in metastatic breast cancer

e11016 Background: Preclinical studies have shown that the combination of an aromatase inhibitor (AI) and oral fluoropyrimidines in estrogen receptor (ER)-positive cell lines enhance antitumor efficacy. This might be explained by reduction of ER-induced growth signaling in addition to decrease in estrogen production. This retrospective analysis of a cohort of patients with metastatic breast cancer (MBC) evaluates the efficacy and safety of combined AI with capecitabine. Methods: Patients with hormone receptor-positive MBC treated with this combination were evaluated and outcomes were compared to women treated with capecitabine (conventional dose) or AI as monotherapy. The administered total dose of capecitabine was 2000 mg. per day in combination with AI. Results: Of 93 patients evaluated, 37 received the combination treatment, 27 capecitabine and 29 an AI. Combination was used in 26 patients as first-line treatment and 11 as second-line. At the time of progression, 92% had a performance status of ≤2 and 58% of patients had visceral disease. No significant difference was observed between the three groups according to clinical and pathological features. Mean follow-up was 23 months (m). The median PFS of first-line treatment was significantly better for the combination (PFS not-reached vs.3.0 m for capecitabine and 13.0 m for AI, p