Extended Adjuvant Aromatase Inhibitor Therapy in Post-Menopausal Women

To understand the evidence for extending adjuvant aromatase inhibitor (AI) therapy from 5 to 10 years in post-menopausal women with hormone receptor positive (HR+) breast cancer.

Multiple large trials have investigated this question. The two trials most representative of the dilemma faced in clinical practice are the MA.17R and NSABP-B42 trials, which both investigated the benefit of continuing versus stopping AI therapy beyond 5 years. Both trials showed that extended AI therapy led to a reduction in new or recurrent breast cancers, but had no effect on survival outcomes when death from any cause was included.

The decision to extend AI therapy beyond 5 years remains a personalized one based on a discussion of the projected risk of recurrence, the expected benefits of prolonged AI treatment, and the patient's ability to tolerate side effects so that quality of life is preserved.