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.