Benefit from adjuvant taxanes and endocrine responsiveness in breast cancer

Several phase III trials have been coincident in showing a benefit with adjuvant taxanes in node-positive breast cancer (BC). These trials provide level I evidence of the efficacy of these drugs. The absolute 5-year DFS gain obtained with the taxane-containing regimens in the positive studies ranged from 4% to 7%. However, the regimens including taxanes are more toxic than the conventional anthracyline-containing combinations. Therefore, the pre-treatment identification of the small proportion of patients who actually benefit from taxanes is of major importance. Several attempts have been made to identify the biological peculiarities of the BC patients who benefit most with taxanes, largely based on retrospective subset analyses. Hormone receptor (HR) status, one of the critical determinants of BC biology, had been suggested to be a factor modulating response to adjuvant chemotherapy in general and taxanes in particular.