http://www.cancernetwork.com/display.../10165/1376582
Much info but skipping to the all-important conclusion:
Conclusions
Despite the recognition of ER as the best predictive factor for endocrine response, a significant number of patients with ER-positive breast cancer do not benefit from endocrine therapy, and the optimum strategy to predict endocrine responsiveness is yet to be defined. Single markers are unlikely to provide precise outcome predictions. Multigene analysis reflecting tumor proliferation and ER pathway genetic activities analyzed by either IHC (Ki67, ER, PR, HER2) or more sophisticated gene-expression profiling (Oncotype DX, MammaPrint, PAM50) on baseline tumors have added prognostic value and are being tested for their utility in predicting the efficacy of systemic therapy. Promising results have also been obtained with the PEPI score, which incorporates tumor size, lymph node status, and Ki67 and ER expression into a prognostic index that is applied to the surgical sample after a patient has received neoadjuvant endocrine treatment.
One can reasonably conclude from this review that even a minimal 2 to 4 weeks of endocrine therapy before surgery will provide additional information over that obtained from a baseline specimen alone, and a large trial has been activated in the UK to address this hypothesis. Ongoing neoadjuvant studies with correlative endpoints and long-term follow-up are critical in addressing these issues as well as getting us to the next step—a complete mechanistic understanding of the reasons for the success or failure of endocrine treatment, so that new mechanism-based therapeutic approaches can emerge.
This article is reviewed at the following links:
Endocrine Therapy in 2009: Consideration of the Tumor and the Host
Predicting Endocrine Responsiveness: Novel Biomarkers on the Horizon