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World J Clin Oncol. Aug 10, 2014; 5(3): 393-405
Published online Aug 10, 2014. doi: 10.5306/wjco.v5.i3.393
Toremifene in the treatment of breast cancer
Mika VJ Mustonen, Seppo Pyrhönen, Pirkko-Liisa Kellokumpu-Lehtinen
Mika VJ Mustonen, Orion Corporation, Orion Pharma, FIN-02101, Espoo, Finland
Seppo Pyrhönen, Department of Oncology and Radiotherapy, Turku University Hospital and University of Turku, FIN-20520, Turku, Finland
Pirkko-Liisa Kellokumpu-Lehtinen, Department of Oncology, University of Tampere, School of Medicine, Tampere University Hospital, FIN-33520, Tampere, Finland
Author contributions: All the authors contributed to the acquisition of data, preparation of the manuscript, reviewing and amending for intellectual content.
Correspondence to: Mika VJ Mustonen, PhD, Orion Corporation, Orion Pharma, Orionintie 1, FIN-02101, Espoo, Finland. mika.mustonen@orionpharma.com
Telephone: +358-50-9664804 Fax: +358-50-9664804
Received: December 18, 2013
Revised: April 8, 2014
Accepted: May 28, 2014
Published online: August 10, 2014
Processing time: 225 Days and 23.7 Hours
Abstract

Although more widespread screening and routine adjuvant therapy has improved the outcome for breast cancer patients in recent years, there remains considerable scope for improving the efficacy, safety and tolerability of adjuvant therapy in the early stage disease and the treatment of advanced disease. Toremifene is a selective estrogen receptor modifier (SERM) that has been widely used for decades in hormone receptor positive breast cancer both in early and late stage disease. Its efficacy has been well established in nine prospective randomized phase III trials compared to tamoxifen involving more than 5500 patients, as well as in several large uncontrolled and non-randomized studies. Although most studies show therapeutic equivalence between the two SERMs, some show an advantage for toremifene. Several meta-analyses have also confirmed that the efficacy of toremifene is at least as good as that of tamoxifen. In terms of safety and tolerability toremifene is broadly similar to tamoxifen although there is some evidence that toremifene is less likely to cause uterine neoplasms, serious vascular events and it has a more positive effect on serum lipids than does tamoxifen. Toremifene is therefore effective and safe in the treatment of breast cancer. It provides not only a useful therapeutic alternative to tamoxifen, but may bring specific benefits.

Keywords: Breast cancer; Toremifene; tamoxifen; Adjuvant treatment; Advanced breast cancer

Core tip: Toremifene is safe and effective in the treatment of breast cancer. Toremifene and tamoxifen are equivalently effective in the treatment of breast cancer, although some studies show an advantage for toremifene. Safety and tolerability is also broadly equivalent, although toremifene may cause fewer uterine neoplasms, serious vascular adverse events and has a more beneficial effect on plasma lipids than does tamoxifen.