| Abstract: |
Endocrine therapy has a firm role in adjuvant treatment of women with hormone receptor-positive invasive breast cancer. Until recently, tamoxifen was the most commonly used adjuvant endocrine therapy in premenopausal and postmenopausal women. Several randomized clinical trials have studied the third-generation selective aromatase inhibitors (Als) (anastrozole, letrozole, and exemestane) as adjuvant endocrine therapy in postmenopausal women. These studies compared therapy with an Al alone versus tamoxifen alone; 2 to 3 years of tamoxifen followed by switching to an Al versus continuation of tamoxifen; or extended therapy with an Al after approximately 5 years of tamoxifen therapy. No statistically significant differences in overall survival were observed. A single trial using extended treatment with an adjuvant Al suggests a small, statistically significant survival advantage in women with axillary lymph node-positive disease while showing no statistically significant decrease in survival with the use of an Al. The toxicities of the Als are generally acceptable, with fewer endometrial cancers, gynecologic complaints, and thromboembolic events, but more bone fractures and arthralgias compared with tamoxifen alone. Three widely disseminated treatment guidelines, the National Comprehensive Cancer Network Breast Cancer Clinical Practice Guidelines in Oncology, the American Society of Clinical Oncology Technology Assessment on the Use of Aromatase Inhibitors, and the St Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer, now incorporate Als in the adjuvant therapy of postmenopausal women with estrogen receptor-positive breast cancer. © Journal of the National Comprehensive Cancer Network. |
