From the Guidelines
Arimidex (anastrozole) is a crucial medication in the treatment of hormone receptor-positive breast cancer, and it should be considered as a first-line adjuvant therapy for postmenopausal women due to its superior efficacy in reducing cancer recurrence compared to tamoxifen, as shown in the most recent and highest quality study 1.
Key Points
- Anastrozole works by blocking the enzyme aromatase, which converts androgens into estrogens in postmenopausal women, thereby reducing estrogen levels in the body.
- It is specifically indicated for postmenopausal women, as it is ineffective in premenopausal women whose ovaries still produce estrogen directly.
- Common side effects include joint pain, hot flashes, bone loss (potentially leading to osteoporosis), and increased cholesterol levels.
- Regular bone density scans are recommended during treatment to monitor for bone loss.
- The most recent study 1 recommends anastrozole as a first-line adjuvant therapy for postmenopausal women with hormone receptor-positive breast cancer, due to its superior efficacy in reducing cancer recurrence compared to tamoxifen.
Treatment Recommendations
- Anastrozole should be prescribed at a dose of 1 mg taken orally once daily, usually for 5-10 years as adjuvant therapy following primary treatment (surgery, chemotherapy, and/or radiation).
- The treatment duration may be extended beyond 5 years, as shown in the study 1, which compared letrozole with placebo for 5 years in women who had already received 4.5 to 6 years of adjuvant therapy with an AI.
Important Considerations
- Anastrozole has a different toxicity profile compared to tamoxifen, with fewer serious side effects such as endometrial cancer and blood clots, but more cases of bone fractures and arthralgias.
- The choice of anastrozole as a first-line adjuvant therapy should be based on individual patient factors, including menopausal status, hormone receptor status, and overall health.
From the FDA Drug Label
Anastrozole tablets are indicated for adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer. Anastrozole tablets are indicated for the first-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer. Anastrozole tablets are indicated for the treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy.
The role of Arimidex (anastrozole) in the treatment of hormone receptor-positive breast cancer is as an adjuvant treatment for postmenopausal women with early breast cancer, as a first-line treatment for postmenopausal women with locally advanced or metastatic breast cancer, and as a second-line treatment for postmenopausal women with advanced breast cancer who have progressed after tamoxifen therapy 2. Key benefits of anastrozole include its ability to lower circulating estrogen levels, which can help slow the growth of hormone receptor-positive breast cancer cells. However, it's essential to consider the potential side effects, such as hot flashes, osteoporosis, and increased risk of fractures, when making treatment decisions 2.
From the Research
Role of Arimidex in Hormone Receptor-Positive Breast Cancer
- Arimidex (anastrozole) is an aromatase inhibitor used in the treatment of hormone receptor-positive breast cancer in postmenopausal women 3, 4, 5, 6.
- It has been shown to be effective in reducing breast cancer recurrence and improving disease-free survival compared to tamoxifen 4, 5, 6.
- Anastrozole can be used as a first-line treatment for advanced breast cancer, and its efficacy has been demonstrated in several clinical trials 3, 5, 6.
Efficacy and Safety
- Studies have shown that anastrozole is well-tolerated and has a favorable safety profile compared to tamoxifen, with fewer thromboembolic events and vaginal bleeding 5.
- The most common adverse effect of anastrozole is an increased risk of bone fractures, which is restricted to the treatment period 4.
Treatment Settings
- Anastrozole can be used in various treatment settings, including neoadjuvant, adjuvant, and extended adjuvant therapy, as well as in the treatment of advanced breast cancer 4, 6.
- It has been shown to be effective in improving disease-free survival and overall survival in postmenopausal women with hormone receptor-positive breast cancer 4, 6.
Comparison with Other Aromatase Inhibitors
- Anastrozole is one of several third-generation aromatase inhibitors, including exemestane and letrozole, which have been shown to be effective in the treatment of hormone receptor-positive breast cancer 6.
- Ongoing studies are comparing the efficacy and safety of these aromatase inhibitors in different treatment settings 6, 7.