Patient-level meta-analysis of extending duration of endocrine treatment for early breast cancer after at least 5 years of endocrine treatment

A patient-level meta-analysis of 12 trials investigated benefits and risk of extending duration of aromatase inhibitor therapy (AIT) among more than 22,000 eligible postmenopausal women with early breast cancer who were recurrence-free after 5 years of tamoxifen, or AIT, or tamoxifen followed by AIT. Extending the duration of AIT with 2-3 years or 5 years was associated with reduction of the risk of recurrence and distant recurrence, and with increased risk of bone fracture. Longer follow-up would have been needed to assess any effects on mortality.