Abstract
Background: Endocrine therapy is an integral part of the backbone for hormone receptor–positive breast cancer treatment. Toremifene and tamoxifen are approved for hormone receptor–positive metastatic breast cancer. Tamoxifen is also approved for use in adjuvant breast cancer; however, tamoxifen may not be appropriate for all patients. The purpose of this presentation is to review and assess available data on the efficacy and safety of toremifene in the adjuvant treatment setting. Methods: Systematic review of the literature. Results: Five prospective trials, one retrospective trial, and a meta-analysis have been published regarding the use of toremifene vs. tamoxifen in the adjuvant setting. A combined analysis of 1,035 women enrolled in two different trials showed similar disease-free survival (DFS), overall survival (OS), and recurrence rates (RR) after a mean 5.5 years of follow-up. A separate study showed similar time to recurrence, risk of recurrence, and OS rates with 3 years of therapy with tamoxifen or toremifene. Another study in patients with 5 years of therapy demonstrated equivalent OS with a median follow-up of 59 months. A recent phase III prospective study in postmenopausal women reported noninferiority of adjuvant treatment with toremifene compared with tamoxifen. Both treatments were safe and well tolerated, with no significant differences in the frequency or severity of adverse events, in each of these adjuvant trials. A retrospective study in premenopausal women examined records from 452 patients and showed similar OS with improved DFS with adjuvant toremifene compared to tamoxifen. Finally, a recent meta-analysis including 3,747 patients reported similar OS, DFS, and safety in patients given adjuvant tamoxifen or toremifene. Conclusion: A series of published studies indicate toremifene is as effective and safe as tamoxifen in the adjuvant setting.
