Inclusion Criteria:

- Woman, 18 years old or upper.

- Patient with advanced breast cancer with HER2 positive histologically confirmed. The
criteria for positivity HER2 are: - IHC 3 + - IHQ2 + with FISH / CISH / SISH positive
for HER2 amplification (*) - FISH / CISH / SISH positive for HER2 amplification (*)
(*) Defined as the ratio of copies of HER-2/neu and copies of centromere of
chromosome 17 (CEP17)> 2.2, or a number of copies of HER-2/neu> 6, as per local
laboratory criteria.

- Patient receiving trastuzumab with or without chemotherapy or hormonal therapy for at
least 4 months.

- No evidence of disease progression (clinical and / or radiological) for at least 4
months before inclusion in the study and with a life expectancy of at least 3 months.

- Adequate performance status: Eastern Cooperative Oncology Group (ECOG) <2.

- Adequate bone marrow function, liver and kidney

- Proper cardiac function (LVEF within normal limits the center, measured by
echocardiography or MUGA).

- The patient must have been informed of the study and must sign and date informed
consent document for entry into the trial.

- The patient must be willing and able to comply with study procedures and be available
to answer the study questionnaires.

Exclusion Criteria:

- Patients with no advanced breast cancer.

- Breast cancer patients with tumors HER2-negative.

- The patient has another active malignancy other than breast adenocarcinoma; are
excluded the non-melanoma skin cancer or any other properly treated in situ
neoplasia. Patients with a history of malignancy, if they bear> 5 years without
evidence of disease could be included.

- The patient has uncontrolled brain metastases.

- Concomitant administration, or in the 4 weeks prior to study entry, of other
experimental treatment.

- Known hypersensitivity to trastuzumab or to any of its components.

- Patients with severe dyspnea at rest or requiring supplemental oxygen. -

- Heart disease or serious medical pathological prevent trastuzumab administration:
documented history of CHF, high-risk arrhythmias uncontrolled angina requiring
medication, clinically significant valvular disease, history of myocardial infarction
or evidence of transmural infarction on ECG or hypertension poorly controlled.

- Presence of any concomitant serious systemic disease that is incompatible with the
study (at the discretion of the investigator).

- The patient is pregnant or lactating. Women of childbearing potential should undergo
pregnancy testing blood or urine within 14 days prior to inclusion as institutional
rules and use a non-hormonal contraceptive suitable: intrauterine device, barrier
method (condom or diaphragm) also used in conjunction with spermicidal cream, total
abstinence or surgical sterilization, during treatment with the study drugs and for 6
months following the end of treatment.