Efficacy of trastuzumab re-therapy in routine treatment of HER2-positive breast cancer patients who relapsed after completed (neo-)adjuvant anti-HER2 therapy.

602 Background: Addition of trastuzumab (Roche; T) to chemotherapy (CT) has improved outcomes in patients (pts) with HER2+ breast cancer at all stages, including locally advanced and metastatic disease. Anti-HER2 re-treatment with T is an increasingly used therapy option for the treatment of recurrent/metastatic breast cancer (MBC). However, limited data on T re-treatment is currently available. Methods: Patients with locally recurrent and/or MBC who received T re-therapy were included in this non-interventional study. Among 232 pts enrolled at 121 sites in Germany, 174 pts (33 locally recurrent disease, 141 MBC) were already sufficiently documented to be analyzed for efficacy of T re-ther…