The objective of this observatory is to evaluate the effecacy of Eribulin in patients with metastatic breast cancer on a recent prescription period.

Part of the data collection will be retrospective and the other part will be prospective for patients started treatment by Eribulin between November 2014 and September 2015. It will allow a better assessment on the safety profile of this drug.

Approximately one third of patients treated for localized breast cancer will present a metastatic evolution and 5% of patients are metastatic immediately.

At this stage, the malignancy is incurable with a median survival from 2 to 3 years.

Metastatic breast cancer treatment is part of a multidisciplinary approach. These two objectives are to prolong survival and improve quality of life. At present, there is no standard after the first line of chemotherapy, with fe strategy studies Eribulin is now a new therapeutic option to consider. Many patients have benefited from this treatment option and it seems interesting to evaluate in real life the effecacy and tolerance of chemotherapy.

Inclusion Criteria:

1. Age ≥ 18 years
2. Patient with breast cancer, histologically proven, metastatic or locally advanced
3. Patient treated by Eribulin between January and October 2014 (for the retrospective part) or between November 2014 and September 2015 (for the prospective part).
4. Patient with at least an assessment of the response to Eribulin

Exclusion Criteria:

1. Presence of other neoplasia
2. Man

The population includes all patients treated by Eribulin for breast cancer whose treatment has been starting between January 2014 and September 2015