Twenty-eight clinical trials were identified. Two trials were included in both groups.
In chemo-endocrine versus endocrine therapy, there were no trials comparing ovarian ablation with and without chemotherapy. Eleven randomised controlled trials (7,301 patients) were identified for chemo-endocrine therapy versus endocrine tamoxifen alone, and 1 trial (408 patients) compared chemotherapy plus MPA with MPA alone.
In chemo-endocrine versus chemotherapy alone, 18 trials (8,965 patients) compared chemotherapy alone with tamoxifen or MPA plus chemotherapy.
In chemo-endocrine versus endocrine therapy alone, 7 of the 11 trials with node-positive tumours reported an advantage in disease-free survival for the combined modality therapy. In the subset of node-negative tumours, 1 trial reported an advantage for the combination. Overall, the results strongly suggested that the addition of standard cytotoxic chemotherapy to tamoxifen is advantageous.
In chemo-endocrine versus chemotherapy alone, 13 trials produced no evidence of benefit. However, the subgroups in 3 of them showed evidence of benefit, and 5 trials demonstrated an advantage for the combined therapy.
Two trials evaluated the issue of chemotherapy plus oophorectomy versus chemotherapy alone. No evidence of a benefit was observed.