The role of aromatase inhibitor (AI) in the treatment of breast cancer.

INTRODUCTION Discussion on the topic with the same title above would never be separated from rising questions such as ‘why does it need endocrine therapy?’ and ‘What is endocrine therapy?’ Aside from that, it has been widely known that development of breast cancer is estrogen dependent. Thus, reducing estrogen level by medical or surgical treatment will result in tumor regression, mainly in those who have high number of estrogen receptor (ER). Tamoxifen therapy which was classified as selective estrogen receptor modulator (SERM) after 5 years surgical treatment would decrease relapse and mortality rate to 47% and 26%. However, patients who had undergone definitive surgical treatment, chemotherapy and hormonal therapy for 5 years and still ‘disease free’ were still facing significant possibility of recurrent disease. This paper is an overview of the role of estrogen and aromatase inhibitor (AI) as widely accepted standard of care for breast cancer in various cancer centre and its expanding role upon tamoxifen in postmenopausal patients.