Preoperative concurrent chemo- and endocrine therapies for women with large operable breast cancer expressing steroid hormone receptors

Preoperative chemotherapy and endocrine therapy yielded low pathological complete remission (pCR) rates in patients with endocrine responsive breast cancer. Patients with large operable (cT2-T3, N0-2, M0), ER ≥10% breast cancer were treated in two consecutive studies with preoperative chemotherapy (Study I: six courses of either fluorouracil, leucovorin, vinorelbine (FLN), or vinorelbine, cisplatin, and continuous infusion of fluorouracil (ViFuP), at the discretion of the treating physician; Study II: capecitabine and oral vinorelbine (CAVINO)). Concurrent letrozole (in association with triptorelin if premenopause) was given. Sixty-five (58 evaluable) and 55 (all evaluable) patients were enrolled in the two studies. In Study I there were 43 objective responders (74%, 95% CI 63-85%), three of whom had pCR. Thirty-nine objective responses (91%) and all pCR were observed in patients with tumors expressing ER ≥50%. In Study II 34 patients (62%, 95% CI 49-75%) had an objective response. Endocrine therapy administered together with new intravenous, containing regimens should be explored in the preoperative treatment of endocrine responsive breast cancer.