Safety and efficacy results of a randomized trial comparing adjuvant toremifene and tamoxifen in postmenopausal patients with node-positive breast cancer. Finnish Breast Cancer Group.

PURPOSE

In this multicenter trial, toremifene 40 mg/d was compared with tamoxifen 20 mg/d, both given orally for 3 years to postmenopausal, axillary node-positive women after breast surgery.

PATIENTS AND METHODS

The first 899 patients (toremifene, n = 459; tamoxifen, n = 440) of the total of 1,480 patients accrued to the trial were included in this scheduled safety analysis. The mean follow-up time was 3.4 years.

RESULTS

The two treatment groups were well balanced with respect to patient and disease characteristics. The subjective side-effect profile was similar in both treatment groups. Slightly more vascular complications (deep vein thromboses, cerebrovascular events, and pulmonary embolisms) were seen among tamoxifen-treated patients (5.9%) as compared with toremifene-treated patients (3.5%) (P: =.11), whereas bone fractures (P: =.09) and vaginal leukorrhea (P: =.05) were more common in the toremifene group. The number of subsequent second cancers was similar. The breast cancer recurrence rate was 23.1% (n = 106) in the toremifene group and 26.1% (n = 115) in the tamoxifen group (P: =.31). When only patients with estrogen receptor (ER)-positive cancer were considered (n = 556), the risk for breast cancer recurrence was nonsignificantly lower among the toremifene-treated women, with a hazards ratio of 0.74 (90% confidence interval, 0.52 to 1.04; P: =.14). The mean time to breast cancer recurrence and overall survival were similar in both groups.

CONCLUSION

The side-effect profile of toremifene resembles that of tamoxifen. The efficacy of toremifene seems to be no less than that of tamoxifen. The trend for fewer breast cancer recurrences in the ER-positive subgroup is encouraging, but a longer follow-up is needed to confirm this.