BACKGROUND. Pathologic complete response (pCR) after neoadjuvant treatment is associated with better outcome among patients with locally advanced breast cancer (LABC). The aim of the treatment is to maximize the rate of pCR, while keeping the incidence of adverse events as febrile neutropenia and infections as low as possible.PURPOSE. The study was initiated in order to evaluate the efficacy and toxicity of using FEC100 as neoadjuvant treatment in LABC. Toxicity were also analyzed among Her-2 positive patients who received FEC100 as adjuvant chemotherapy.PATIENTS AND METHODS. Single center retrospective survey. The medical records of 106 patients who received FEC100 at Ullevål University Hospital in the period of 01.05.2005-23.05.2007 were reviewed. FEC100 consists of 5-FU 600 mg/m2, Cyclophosphamide 600 mg/m2 and Epirubicin 100 mg/m2, all administered on day 1 every third week. 53 patients received FEC100 as neoadjuvant treatment, while 53 patients received it as adjuvant treatment. RESULTS. 28,3% of 53 patients with LABC achieved pCR. The pCR rate were 42,9% for the hormone receptor negative and 18,8% for the hormone receptor positive. 24,5% of 106 patients were hospitalized because of febrile neutropenia. The median of the lowest nadir values of neutrophil granulocytes was 0,3 x 109/l.CONCLUSION. The pCR rate achieved in this study is better than in 18 of 21 studies presented in a recently published review article of neoadjuvant chemotherapy for LABC.The incidence of febrile neutropenia is of such magnitude that it should be considered giving Neulasta (G-CSF) as prophylaxis for every patient receiving FEC100.