This study will describe the treatment paradigm used over recent years in the clinical management of Human Epidermal Growth Factor Receptor 2 (HER2)+ metastatic breast cancer in Hungary. This information will provide insight into real-world exposure and adherence to anti-HER2 therapy containing regimens, and improve understanding of the reasons for discontinuation of this therapy.

This is a retrospective, descriptive, cohort study of approximately 180 female patients diagnosed with HER2-positive metastatic breast cancer in Hungary. Patients diagnosed with, or who progressed to, metastatic disease between 01 September 2009 and 01 September 2010 will be included. All patients will be followed until death, loss to follow-up or the end of the study period (30 September 2012). All data will be collected retrospectively from patient medical records.

Descriptive statistics of the demographic and clinical characteristics of HER2+ metastatic breast cancer patients, including sites of metastases, the time from initial breast cancer diagnosis until diagnosis of metastatic disease, and HER2 testing methodology and status of HER2 will be described. Further, descriptive statistics of the proportion of HER2+ metastatic breast cancer patients who received anti-HER2 therapy, the sequencing of different therapies, and the duration of therapies in the metastatic setting will be analysed. Among the subset of women who receive lapatinib plus capecitabine, descriptive statistics of the timing of initiation of lapatinib plus capecitabine in the metastatic treatment pathway, time to treatment discontinuation and time to progression (TTP) on lapatinib plus capecitabine will be calculated. Further, descriptive statistics of the type and duration anti-HER2 therapies used prior to initiation of lapatinib plus capecitabine and, where relevant, after lapatinib+capecitabine will be performed.

Inclusion Criteria:

• Female patients aged 18 years or older at diagnosis of, or progression to, metastatic breast cancer
• Patients with a diagnosis of breast cancer with documented metastatic disease and with known date of metastatic disease
• Patients with a histologically confirmed HER2+ breast cancer (HER2 testing procedures per routine institutional practice; no tissue re-sampling will be performed. If conducted at another site, documented results must be available).

Exclusion Criteria:

• Patients receiving care for another primary cancer during the study time period.

It is planned to capture data on approximately 180 patients with HER2-positive metastatic breast cancer in about 20 medical centres in Hungary. Patients diagnosed with, or who progressed to, metastatic disease between 01 September 2009 and 01 September 2010 will be included. All patients will be followed until death, loss to follow-up or the end of the study period (30 September 2012).