Status of aromatase inhibitors in relation to other breast cancer treatment modalities.

Aromatase is one of the key enzymes possibly linked with the perpetuation or even initiation of breast cancer. Modulation of its activity by the new generation inhibitors has resulted in increased responses and improved therapeutic ratio compared with those of parent aromatase inhibitors. More recent trials have shown promising results with regard to improved therapeutic ratio compared with what is seen with presently accepted second-line hormonal approaches. Present data and laboratory research indicate that new aromatase inhibitors have the potential to play an important role as adjuvants, and possibly in the prevention of human breast cancer. It is probable that it may be as adjuvants that their real therapeutic strength in terms of a beneficial impact on survival may be realized. The absence of estrogen agonist activity of new aromatase inhibitors on lipid and bone metabolism calls for more clinical studies having late mortality in breast cancer survivors as the ultimate outcome objective; in this regard, interaction of new aromatase inhibitors with new selective estrogen receptor modulators looks promising. Achievement of these outcomes, and understanding of interactions with other therapies, await the termination of present trials and the start of new initiatives.