21153 Background: Preoperative chemotherapy and endocrine therapy yielded low pathological complete remission (pCR) rates in patients with endocrine responsive breast cancer. Methods: Patients with large operable endocrine responsive (ER ≥ 10% of the cells) breast cancer (cT2-T3, N0–2, M0) were treated in 2 consecutive studies with preoperative chemotherapy (Study I: 6 courses of either fluorouracil, leucovorin, vinorelbine (FLN), or vinorelbine, cisplatin, and continuous infusion of fluorouracil (ViFuP), chosen at the discretion of the treating physician; Study II: an oral regimen with capecitabine and vinorelbine (CAVINO). In both studies concurrent endocrine therapies (letrozole, either alone or if premenopause, with triptorelin) were given. Results: Sixty-five (58 evaluable) and fifty-five (all evaluable) patients were enrolled to Studies I and II, (ER >50%, 51 and 50; Ki 67 = 20%, 42 and 39; cT2/3: 36 / 22 and 35 / 20; premenopausal 40 and 38) respectively. In Study I there were 43 objective responders (74%, 95% CI 63–85%), 4 of whom had pCR. In Study II 34 patients (62%, 95% CI 49–75%) had an objective response. Breast conserving surgery became possible for 64% and 62% of the patients in Study I and II, respectively. Conclusions: Intravenous, non anthracycline containing regimens together with tailored menopause status-adapted endocrine therapy, warrants further investigations in the preoperative setting. No significant financial relationships to disclose.