Abstract
Trastuzumab administered in combination with various chemotherapy regimens has led to outstanding improvements in both disease-free survival and overall survival. So far, thousands of patients have been treated in this way which has proven to be reasonably safe, with cardiac events being the predominant recognisable toxicity requiring surveillance. Notwithstanding the large cumulative experience of the oncology community in treating early HER2/neu-positive breast cancer with trastuzumab, some uncertainties remain, with key issues being the ideal time of chemotherapy administration and the optimal duration of trastuzumab therapy. This paper discusses these issues in the light of the recent updates of some of the pivotal clinical trials in the adjuvant context.