This retrospective cohort study aims to improve our understanding of the current paradigm for treatment of brain metastases in erbB2+ breast cancer patients in the Asia Pacific region. We aim to identify approximately 300 erbB2+ breast cancer patients with brain metastases diagnosed between 2006-2008 in 6 countries. Medical records will be analyzed to determine the treatment pattern for brain metastases, including anti-erbB2 therapy. Additional objectives are to understand the impact of anti-erbB2 therapy on survival after brain metastases and to investigate the relationship between anti-erbB2 therapy for brain metastases and: 1) the time interval between diagnosis of erb2+ breast cancer and brain metastasis, and 2) the occurrence of brain metastasis as the first site of disease progression.

Inclusion Criteria:

1. Female patients diagnosed with erbB2+ breast cancer. ErbB2 positivity will be as determined by respective institutional standards, and will be based on medical history only.
2. Brain metastasis diagnosis made between January 2006 - December 2008.

Exclusion Criteria:

1. Women who have another primary cancer diagnosed between the time of breast cancer diagnosis and brain metastasis..
2. Patient has leptomeningeal metastases only without parenchymal brain involvement (since this pattern of the disease requires a different treatment approach.)

This study aims to enrol approximately 300 Erb2+ breast cancer cases with brain metastases in 6 Asian countries (Indonesia, Korea, Malaysia, Philippines, Singapore, and Thailand).