Toremifene is an effective and safe alternative to tamoxifen in adjuvant endocrine therapy for breast cancer: results of four randomized trials

Compared to tamoxifen, the efficacy and side effects of toremifene in adjuvant endocrine therapy for breast cancer were not very clear. This meta-analysis was conducted to give a more precise estimation of the efficacy and severe side effects of toremifene given in the adjuvant setting in comparison to tamoxifen. The electronic database PubMed was searched for randomized trials comparing toremifene with tamoxifen as adjuvant therapies. Four randomized trials published in three articles were eligible, including 1,890 pooled cases treated with toremifene and 1,857 cases treated with tamoxifen. Compared to patients in tamoxifen group, patients in toremifene group did not have a significantly different overall survival rate (risk ratio (RR): 1.07, 95% confidence interval (CI): 0.97-1.19, P = 0.994 for heterogeneity) or a disease-free survival (DFS) rate (RR: 1.05, 95% CI: 0.95-1.17, P = 0.431 for heterogeneity) at the end of the follow-up time. The rates of thromboembolic events in toremifene group, including deep vein thrombosis (odds ratio (OR): 0.68, 95% CI: 0.40-1.17, P = 0.926 for heterogeneity), cerebrovascular accident (OR: 0.59, 95% CI: 0.32-1.09, P = 0.438 for heterogeneity), and pulmonary embolism (OR: 0.91, 95% CI: 0.42-2.01, P = 0.618 for heterogeneity), were not significantly different from those in tamoxifen group. The rates of endometrial polyps and endometrial cancer between the two groups were almost the same. This meta-analysis suggested that toremifene was as effective as tamoxifen in the adjuvant setting for both perimenopausal and postmenopausal breast cancer patients with similar severe adverse effects to tamoxifen. Toremifene was a convincing and safe change for tamoxifen in adjuvant endocrine therapy.