This single arm, prospective, observational study will assess the correlation between the time from start of chemotherapy to the start of Avastin (bevacizumab) treatment with progression-free survival in patients with previously untreated metastatic breast cancer. Patients will be followed for up to 12 months after progressive disease occurs.

Inclusion Criteria:

• Adult patients, >/=18 years of age
• Previously untreated metastatic breast cancer
• Scheduled to start 1st line chemotherapeutic treatment
• ECOG performance status 0-1

Exclusion Criteria:

• Any conditions included in contraindication list for Avastin
• Prior chemotherapy for metastatic breast cancer
• Adjuvant/neoadjuvant chemotherapy or radio-chemotherapy of non-metastatic malignancy completed <6 months prior to treatment start

Female patients with metastatic HER2 negative breast cancer. First-line treatment with Avastin