Recruitment Target not met

This is a prospective, national, multicenter, non-interventional study designed to enroll participants who have an initial diagnosis of unresectable LA/mBC made up to 6 months prior to registry enrollment. These participants will be prospectively followed for at least 5 years after study enrollment to evaluate their anti-cancer treatments. Data on participants' previous anti-cancer treatments for breast cancer will be collected retrospectively at study entry.

Inclusion Criteria:

• Initially diagnosed with HER2-positive unresectable LA/mBC no more than 6 months prior to enrollment
• Able to comply with the study protocol

Exclusion Criteria:

None

Participants with HER2-positive unresectable LA/mBC