Eligibility NCT00545077 Breast Cancer Inclusion Criteria age 18 Years to 80 Years Yes
No
Before starting the specific protocol procedures, the written informed consent must be obtained and documented. Yes
No
Women >=18 years. Yes
No
Capacity to comply with all the protocol requirements. Yes
No
Functional ECOG status <= 1. Yes
No
Life expectancy >= 24 weeks. Yes
No
Histologically confirmed breast adenocarcinoma, with measurable or non-measurable, locally advanced or metastatic (stage IV) disease. In the event that the patient only has locally advanced disease, she will not be able to undergo curative local treatment. Patients with metastasis confined to the bone can be chosen, but the disease must be confirmed by radiology, CT scan or NMR if there is any doubt after a single bone scan. Yes
No
Patients with HER2-negative disease evaluated by IHC and FISH/CISH (IHC 0 or 1+, or 2+ and negative FISH). Patients with 3+ by IHC cannot be chosen regardless of the FISH/CISH status and those with positive FISH/CISH (> 2 amplifications) cannot be chosen either, regardless of the IHC findings. Yes
No
Positive hormone receptors (estrogen receptor [ER] and/or progesterone receptor [PgR]) evaluated by a local or central laboratory, according to the criteria of the participating institution. Yes
No
Patients who are candidates for receiving first-line treatment with letrozole. Yes
No
Patients may have received (neo)adjuvant chemotherapy, provided that the last dose of the latter was received at least 12 months before randomization . Patients must be recovered from toxicity. Yes
No
The patients are allowed to have received adjuvant radiotherapy, provided that it was completed at least 6 weeks before randomization and the patient has recovered from the reversible acute effects of the radiation. The previous administration of radiotherapy to palliate the pain of bone metastases is authorized, provided that: Yes
No
Not more than 30% of bone marrow has been irradiated. Yes
No
The patient has recovered from the reversible acute effects of the radiation. Yes
No
The patient has at least one metastatic location which has not been irradiated and which may be evaluated for progression, or a clear progression of the bone disease has been objectified after the end of the palliative radiotherapy. Yes
No
Exclusion Criteria 
