Use of Endocrine Therapy for Breast Cancer Risk Reduction: ASCO Clinical Practice Guideline Update.

Purpose: To update the ASCO guideline on pharmacologic interventions for breast cancer risk reduction and provide guidance on clinical issues that arise when deciding to use endocrine therapy for breast cancer risk reduction.

Methods: An Expert Panel conducted targeted systematic literature reviews to identify new studies.

Results: A randomized clinical trial that evaluated the use of anastrozole for reduction of estrogen receptor-positive breast cancers in postmenopausal women at increased risk of developing breast cancer provided the predominant basis for the update.