Phase II study of high dose toremifene in advanced breast cancer progressing during tamoxifene treatment.

Thirty-five (34 evaluable) consecutive postmenopausal women with estrogen receptor positive (greater than or equal to 10 fmol/mg) or unknown advanced breast cancer were treated with high dose toremifene in a phase II study. All patients had progressed during prior adjuvant or palliativ antiestrogen treatment. The dose of toremifene was 240 mg per day. No complete or partial responders were registered. Nine patients (26%) were considered to have stable disease (NC). The time to progression for these patients was 5-27+ months with a mean time of twelve months and median time of eight months. Two patients are still on treatment after twelve and 24 months respectively. There seems to be a relationship with receptor value; however, there are two few patients for a safe statistical analysis. The side effects were insignificant. The conclusion is that the efficiency of toremifene as second line hormonal treatment is restricted, although it may be one additional choice.