Neoadjuvant Endocrine Therapy for Estrogen Receptor-Positive Breast Cancer: A Systematic Review and Meta-Analysis

Authors: Spring, L. M. et al.

Source: JAMA Oncol., doi:10.1001/jamaoncol.2016.1897

www.ncbi.nlm.nih.gov/pubmed/27367583

Neoadjuvant (pre-operative) therapy is used in breast cancer to essentially shrink the disease and allow for more successful or more desirable surgery (clear margins, conversion to lumpectomy instead of mastectomy). Traditionally, that neoadjuvant therapy has consisted of standard chemotherapy. Chemotherapy bears well-known and severe toxicities. On the other hand, aromatase inhibitors are much better tolerated and have fewer serious side effects.

The investigators performed an extensive review of all qualified, available studies to evaluate the ability of aromatase inhibitors in the neoadjuvant setting (NET) to have the same surgical outcomes as neoadjuvant chemotherapy (NACT). Subjects were almost entirely postmenopausal women with ER+ breast cancer who received either NACT or NET.

There were no significant differences between these two groups regarding clinical response rate (palpable disease), radiological response rate (measured disease by mammogram and/or ultrasound) or rate of lumpectomy. There was also no difference in the response of the disease to either therapy. However, toxicities were significantly higher among the patients receiving NACT.

This analysis demonstrated that NET for postmenopausal women with ER+ breast cancer resulted in equivalent clinical disease responses and allowed for the same amount of lumpectomies as NACT, with fewer adverse side effects. This promising information opens the door to explore which combinations of NET are best, and which patients are the most appropriate candidate for it.