Meeting highlights: international expert consensus on the primary therapy of early breast cancer 2005.

The ninth St Gallen (Switzerland) expert consensus meeting in January 2005 made a fundamental change in the algorithm for selection of adjuvant systemic therapy for early breast cancer. Rather than the earlier approach commencing with risk assessment, the Panel affirmed that the first consideration was endocrine responsiveness. Three categories were acknowledged: endocrine responsive, endocrine non-responsive and tumors of uncertain endocrine responsiveness. The three categories were further divided according to menopausal status. Only then did the Panel divide patients into low-, intermediate- and high-risk categories. It agreed that axillary lymph node involvement did not automatically define high risk. Intermediate risk included both node-negative disease (if some features of the primary tumor indicated elevated risk) and patients with one to three involved lymph nodes without additional high-risk features such as HER 2/neu gene overexpression. The Panel recommended that patients be offered chemotherapy for endocrine non-responsive disease; endocrine therapy as the primary therapy for endocrine responsive disease, adding chemotherapy for some intermediate- and all high-risk groups in this category; and both chemotherapy and endocrine therapy for all patients in the uncertain endocrine response category except those in the low-risk group.