Letrozole and Metronomic Capecitabine in ER-positive HER2 Negative Advanced Breast Cancer (B-001 Study)

Inclusion Criteria:

* Female sex
* Age 18-70
* ECOG-PS 0-II.
* Histopathological proof of breast cancer
* ER positive (Allred score of ≥3 out of 8), and HER2 negative by IHC (or ISH if HER2 +2).
* Metastatic/recurrent disease as proven by CT scan, bone scan or clinical examination (for skin lesions). Biopsy of the recurrent lesions is encouraged but not mandatory.
* Either hormone sensitive setting (Denovo metastatic disease or disease progression after more than 1 year of ending adjuvant endocrine therapy) or secondary resistance to tamoxifen therapy (disease relapse after more than 2 years of starting and less than 1 year of ending adjuvant endocrine therapy, or DP of metastatic disease after more than 6 months of first line tamoxifen).
* Adequate organ function.
* Signed informed consent

Exclusion criteria:

* Inadequate organ functions.
* Disease progression while on prior aromatase inhibitor therapy.
* Primary endocrine resistance.
* Double primary cancer (history of other malignancy apart from a non melanoma skin cancer).
* Refusal to sign consent.