Metastatic breast cancer: Tailored endocrine therapy for postmenopausal women

Abstract

Until about a decade ago, the standard endocrine therapy for all women with hormone- receptor positive breast cancer was tamoxifen, regardless of age, menopausal status, or stage of disease. The only molecularly tailored aspect of the use of tamoxifen was the recognition that it was only effective against breast cancers that expressed estrogen receptors (ERs). Patient-tailored therapy might otherwise be termed "good clinical judgment" regarding who was treated with an endocrine agent and when. However, the approval of third-generation specific aromatase inhibitors (AIs) saw a paradigm shift because efficacy considerations could now also be taken into consideration. In addition, the simple mode of action exhibited by AIs as a class gave rise to new insights into the molecular basis of estrogen-dependent malignancies. This chapter summarizes the current clinical literature, with an emphasis on how molecular insights might translate into new treatment approaches. Our abilities to tailor, at the molecular level, endocrine treatments for advanced disease through molecular biomarkers remains rudimentary, but progress in the analysis of breast cancer at the genomic level may make truly tailored therapy a reality. © Springer-Verlag Berlin Heidelberg 2006.