Replacing tamoxifen with an aromatase inhibitor in premenopausal women receiving ovarian suppression therapy significantly decreases the risk of breast cancer recurrence, a meta-analysis shows.

However, use of the agents — including anastrozole, exemestane or letrozole — appeared to have no impact on breast cancer mortality, an international research collaboration has found.

Using individual patient-level data from four randomised trials, the University of Oxford-led team examined whether premenopausal women with breast cancer receiving ovarian suppression (goserelin or triptorelin) or ablation could benefit from aromatase inhibitors compared with tamoxifen.

The pooled cohort included 7030 women aged in their 40s with early-stage oestrogen receptor-positive breast tumours, 60% of whom had node-negative cancer.