Weighing the Individual Risk for Breast CancerEditor's Note: The American Society of Clinical Oncology (ASCO®) issued the latest update to its guideline on pharmacologic interventions for breast cancer risk reduction in July 2013. [1,2]
The guideline focused on the risks/benefits of pharmacologic intervention vs no pharmacologic intervention, the comparative efficacy of breast cancer chemoprevention agents, and how physicians should communicate issues regarding breast cancer risk reduction in women with increased risk (ie, a 5-year projected absolute risk of ≥ 1.66%). The basis for the update was new evidence from randomized controlled trials and meta-analyses published since the previous update in 2009. 
This evidence led to strengthened recommendations to consider using tamoxifen (20 mg per day for 5 years) in pre- and postmenopausal women who are at increased risk for invasive breast cancer, specifically estrogen-receptor (ER)-positive breast cancer, and raloxifene (60 mg per day for 5 years) or exemestane (25 mg per day for 5 years) as an option in postmenopausal women. No recommendation is made for the use of other selective estrogen receptor modulators (SERMs) or other aromatase inhibitors to lower breast cancer risk outside of a clinical trial.
The guideline strongly encourages healthcare providers to discuss the option of chemoprevention, including the specific risks and benefits associated with each agent, with women at increased breast cancer risk.