Six RCTs (2,657 patients) were included in the review.
There was a significant difference in favour of aromatase inhibitors for overall response rate (OR 1.56, 95% CI 1.17 to 2.07; six trials; Ι²=58.1%) and clinical benefit (OR 1.70, 95% CI 1.24 to 2.33, six trials; Ι²=70.2%). There was no significant difference between groups for the analysis of overall survival (three trials) or response by oestrogen/progesterone receptor status (three trials).
Significantly more adverse events were reported in the tamoxifen group for vaginal bleeding (OR 0.30, 95% CI 0.16 to 0.56; four trials) and thromboembolic events (OR 0.47, 95% CI 0.28 to 0.77, three trials) with no significant heterogeneity. No other statistically significant results were found for adverse events.
There was no evidence of publication bias (results not shown).