Six vs 12 Months of Trastuzumab With Docetaxel Following FEC as Adjuvant Treatment in N+ Breast Cancer

Inclusion Criteria: * Women with histologically-confirmed unilateral invasive ductal or lobular breast adenocarcinoma * HER2/c-neu over expression should be documented by either immunohistochemistry (score 3+) or FISH/CISH positivity. A score of 2+ by immunohistochemistry is acceptable only if FISH/CISH positive * Within 60 days after the surgical excision of the primary tumor with tumor-free operation margins; at least 10 axillary lymph nodes have to be removed. * Tumor involvement of at least one axillary lymph node (N0 with HER2/c-neu over expression are also eligible) * Absence of any clinical or radiological evidence of local or metastatic disease * Premenopausal or postmenopausal women aged 18-75 years old * Adequate bone marrow function (absolute neutrophil count \>1500/mm3, platelet count \>100.000/mm3, hemoglobin \>10gr/mm3) * Adequate liver (bilirubin \<1.0 times upper limit of normal and SGOT/SGPT \<2.5 times upper limit of normal) and renal function (creatinine \<1.5mg/dl) * Adequate cardiac function (LVEF\>50%). Normal electrocardiogram and absence of significant heart disease * Written informed consent Exclusion Criteria: * Positive pregnancy test. * Psychiatric illness or social situation that would preclude study compliance. * Other concurrent uncontrolled illness. * Prior or concurrent antineoplastic therapy e.g. hormonal therapy, radiation therapy, chemotherapy, biological agents. * Previous history of other invasive malignancy other than non-melanomatous skin cancer.