Data suggest that greater than one-fourth of patients with estrogen receptor–positive metastatic breast cancer who are treated with an aromatase inhibitor (AI) will develop a mutation in the ESR1 gene, conferring resistance to the AI. Response after AI failure is poor, leading to a search for better therapeutic options.
Fulvestrant was found to extend progression-free survival compared with anastrozole in postmenopausal women with hormone receptor–positive locally advanced or metastatic breast cancer who have not received previous endocrine therapy.
The use of the investigational CDK4/6 inhibitor abemaciclib, in combination with an aromatase inhibitor or with fulvestrant, or as monotherapy, has demonstrated efficacy in patients with HER2-negative/hormone receptor–positive breast cancer in multiple settings.
Updated National Comprehensive Cancer Network guidelines for the management of breast cancer address the use of genomic expression profiling in predicting distant recurrence as well as the benefit of adjuvant endocrine therapy and adjuvant chemotherapy.
New guidance from the National Comprehensive Cancer Network (NCCN) defines appropriate radiation treatment targets, noting that individualizing radiation therapy based on risk is important, and that hypofractionation is now the preferred method of delivery to achieve local control and acceptable breast cosmesis.
A sophisticated gene signature test has been shown to enhance the prediction of the clinical efficacy of chemotherapy in women with early-stage breast cancer, according to results of the recent phase 3 MINDACT study. The findings will enable many women to safely avoid chemotherapy.