While therapeutic strategies for HER2-positive breast cancer are well defined, there is not a standard strategy for HER2-negative tumors.

Because of lack of information related to the the factors affecting the choice of a particular treatment strategy, as well as the optimization of the correct sequence of treatments, the choice of the treatment for the advanced disease remains highly empirical and may differ significantly among the different cancer centers.

The purpose of this study is the observation of a cohort of patients with metastatic HER2-negative in terms of:

1. the choice of chemotherapy treatments starting from the first line of treatment;
2. factors that may influence these choices;
3. correlation among the characteristics of patients (age, menopausal status, etc.) and type of adjuvant and metastatic treatment ;
4. clinical outcome (pattern of relapse, time from diagnosis, etc.);
5. evaluation of the adherence to the literature's recommendations for therapeutic sequences in clinical practice.

In particular, the attention will be on those factors, largely discussed in the literature, that predominantly guide the choice among different therapeutic approaches such as:

• metastatic sites;
• hormone receptor status;
• disease-free interval;
• grading;
• response to a previous treatment with hormonal therapy or chemotherapy. The primary objective is the description of medical therapeutic strategies for the first, the second and the subsequent lines of chemotherapy in a cohort of patients with HER2-negative metastatic breast cancer and the evaluation of the possible correlation between the choice of treatment, in the adjuvant phase or for the metastatic disease and also for the patients' characteristics (age, menopausal status, comorbidity).

the secondary objectives are:

• Analyze the "Time to Treatment Change", defined as the interval of time that elapses from the start of chemotherapy to the discontinuation or the occurrence of any other event. This finding is of a particular clinical relevance, since randomized trials using the "Time To Progression" (TTP) as a measure of effectiveness of the treatment in the study, but this time parameter may not correspond to what is observed in clinical practice, where the revaluations of disease are not conducted at preset intervals as is in the case of controlled clinical trials.
• Evaluate the correlation between the characteristics of the patients and the choice of the type of chemotherapy.
• Assess the potential correlation between the type of adjuvant therapy and the type of response obtained with the first-line treatment and between the answer to this last therapy line and second/third one.
• Assess the adherence to the literature's recommendations (Consensus Conferences and Guide-lines) of the choices between the sequential therapy vs the combination therapy in different lines of treatment (first, second, third line) of the metastatic disease.

Inclusion Criteria:

1. Patients with HER2-negative metastatic breast cancer (Stage IV), that have received or not the endocrine therapy for the metastatic disease and that are candidate for the first-line chemotherapy treatment in the years 2014-2015 (prospective cohort), or patients that have received a treatment of first, second or subsequent-line of chemotherapy for the metastatic disease in the years 2012-2013 (retrospective cohort).

2. Age > 18 years

3. Availability of all information required by the study, in particular:

   • histology
   • hormone receptor status
   • grading
   • stage of disease at diagnosis
   • type of surgery for the primary tumor
   • type of adjuvant therapy (chemotherapy or hormone therapy)
   • type of medication received as adjuvant therapy
   • date and seat of the relapse
   • type of treatment received for the first / second / third-line of treatment of metastatic disease (chemotherapy or hormone therapy)
   • type of chemotherapy regimen used and details about the medication, date and seat of disease progression

4. Written informed consent (in case of the impossibility to obtain the consent in writing, eg, death of the patient, the data will be collected as required by the Guarantor, OJ N.72 of March 26, 2012)

Exclusion Criteria:

1. Patients with metastatic disease at diagnosis
2. Patients with HER2-positive breast
3. Participation in clinical research protocols, both for the retrospective cohort and for the perspective one

Female patients from Italy with metastatic breast cancer.