The clinical benefit of high-dose toremifene for metastatic breast cancer.

Abstract Toremifene(TOR)is a selective estrogen receptor modulator(SERM). A high dose of 120 mg TOR(HD-TOR) has been used for recurrent breast cancer in Japan, but there is still insufficient evidence regarding the efficacy of HD-TOR. HD-TOR was administered for recurrent or metastatic breast cancer between January 2003 and May 2012. The primary end point of the study was the tumor response rate. Bone metastasis cases were excluded from the efficacy analysis, but were included in the safety population. A total of 21 patients registered in the study and the 2 patients with bone metastasis only were excluded from the efficacy analysis. The median follow-up period was 8. 3 months. None of the patients in the study had a CR, 4 had a PR(21. 1%), 9 had SD(47. 4%), and 6 had PD(31. 6%). Eight of the 9 SD cases had a long-term SD. The ORR was 21. 1% and the CB rate was 63. 2%. The median TTP of CB cases was 18. 3 months. None of the patients discontinued treatment because of a grade 3 or grade 4 adverse effects. In summary, the current study showed that HD-TOR may lead to a CB for recurrent breast cancer in first- or second-line treatment rather than thirdline. In particular, HD-TOR may give a benefit in highly endocrine-sensitive cases.