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Ruth M. O'Regan, MD

Articles by Ruth M. O'Regan, MD

With the advent of aromataseinhibitor use in the adjuvantsetting,[1] and the inceptionof trials examining their usefor breast cancer prevention, it seemsprudent to evaluate what we know todate about the long-term effects of these agents. Unfortunately, unlike selectiveestrogen-receptor modulators(SERMs)-in particular tamoxifen,[2]which has been used for over 15 yearsin patients with early-stage breast cancer-long-term data on the use of aromataseinhibitors are minimal.

The use of aromatase inhibitorshas increased dramatically inthe past few years as a resultof the emergence of new, more specificagents, such as anastrozole(Arimidex), exemestane (Aromasin),and letrozole (Femara). This class ofagents effectively blocks the peripheralformation of estradiol, decreasingits concentration to less than 10%,while maintaining selectivity.[1]Evaluation of these selective aromataseinhibitors as adjuvant therapyfor early-stage breast cancer wasbased on the findings of trials inmetastatic breast cancer, summarizedby Visvanathan and Davidson, thatdemonstrated the equivalence and,in some cases, superiority of thearomatase inhibitors comparedwith megestrol and tamoxifen,including their superior side-effectprofile.[2-4]