Efficacy of extended aromatase inhibitors for hormonereceptor - positive breast cancer: a literature based meta-analysis of randomized trials

•Adjuvant endocrine therapy reduces the risk of recurrence and increases survival rates in breast cancer patients.•The benefit of extended adjuvant endocrine therapy with aromatase inhibitors (AIs) is currently being debated.•Our retrospective analysis of 8 randomized clinical trials provides evidence of a disease free survival (DFS) benefit with extended adjuvant AIs therapy.•DFS benefit was higher in patients with positive nodal status.•Identification of new biomarkers could help identify specific subgroups of patients able to benefit from extended adjuvant endocrine therapy with AIs.