Neo-adjuvant Chemotherapy With Letrozole in Patients With Estrogen Receptor Positive/HER-2 Negative Breast Cancer

STUDY RATIONALE: Patients with ER+/HER2- operable breast cancers who are candiate of neoadjuant chemotherapy generally receive chemotherapy alone before operation, followed by adjuvant endocrine therapy. Because endocrine therapy is primarily delivered in the postoperative setting, the ability to add the efficacy of aromatase inhibitors combined with chemotherapy is lost. This study offers the unique opportunity to assess the synergistic or additive responsiveness of breast tumors to endocrine therapy plus chemotherapy while the tumors are still in vivo by treating patients with an aromatast inhibitor combined with chemotherapy before surgery and assessing pCR rates. PRIMARY OBJECTIVE: The primary objective is to determine the frequency of pCR in breast and axilla.