Anastrozole is a nonsteroidal aromatase inhibitor used mainly in the treatment of hormone receptor–positive breast cancer in postmenopausal women, where it works by blocking the aromatase enzyme and thereby reducing estrogen production, which in turn slows the growth of estrogen-dependent tumors; because of this targeted mechanism, it has become an important alternative to older therapies such as Tamoxifen, offering improved outcomes in many patients. The drug was developed by AstraZeneca in the late 20th century as part of a new class of endocrine therapies, and after successful clinical trials demonstrating its effectiveness and better tolerability, it was approved in 1995; since then, it has played a major role in breast cancer management, especially following large studies like the ATAC trial, which confirmed its superiority in reducing recurrence rates, establishing anastrozole as a cornerstone of modern cancer treatment.
