A meta-analysis by the Early Breast Cancer Trialists' Collaborative Group (EBCTCG) synthesizes the randomized evidence for extended aromatase inhibitor therapy after at least 5 years of prior endocrine therapy in patients with early breast cancer.[1][2] Extended therapy with aromatase inhibitors significantly reduces the risk of recurrence by 33% after prior tamoxifen therapy and by 19% after partial aromatase inhibitor therapy.[2] Overall, therapy reduces the risk of invasive breast cancer recurrence by 27% (RR 0.73; 95% CI 0.67-0.80; p < 0.0001).[4] It reduces the risk of distant recurrence by 15% (6.1% vs. 5.1%; p = 0.004) and the risk of breast cancer mortality is not significantly affected.[2] The benefit is greater after previous treatment with tamoxifen alone than after a combination with aromatase inhibitors.[2][4] Extended therapy does not increase the risk of fatal grade 3 or higher adverse events.[1] These findings confirm a proportional reduction of recurrence in selected patients.[1]