Trastuzumab treatment in patients with advanced breast cancer (ABC) confined to locoregional and skeletal sites: Results from a large noninterventional study.

640 Background: In a prospective observation study routine trastuzumab (T) treatment in HER2+ ABC was evaluated in a total of 1,687 patients (pts) since 2001. This large number allows the subgroup analysis of patients with the involvement of specific sites. Methods: Information on extent of advanced disease was available in 1,674 pts (99%) with HER2 overexpressing ABC. Pts were either pre-treated (39%) or naive to palliative chemotherapy (CT). The following subgroups and their characteristics were analysed: I: locally ABC only; II: bone metastases allowing for concomitant local tumour; III: other. Results: Locally advanced lesions were found to be the sole BC manifestation in 145 pts (8.7%), while bone metastases ± locally ABC were found in 209 pts (12.5%). This leaves a comparative population of 1320 pts with metastases to other sites, predominantly visceral metastases. The table shows the baseline and treatment characteristics, as well as the long term outcome based on progression/death observed in 79%/...