OBJECTIVE: To assess the effects of tibolone on climacteric symptoms, endometrium and serum lipid/lipoproteins in postmenopausal women receiving tamoxifen after surgery for breast cancer.

DESIGN: Double-blind, randomised, placebo-controlled, multicentre pilot study.

SETTING: Hospital outpatient clinic.

SAMPLE: Seventy postmenopausal women receiving tamoxifen following surgery for early breast cancer.

METHODS: Women received 20 mg/day oral tamoxifen plus either 2.5 mg/day oral tibolone or placebo for 12 months.

MAIN OUTCOME MEASURES: Frequency and severity of hot flushes (diary cards); intensity of hot flushes and sweats (Landgren scale); interference of hot flushes and sweats with normal life; frequency and intensity of other climacteric symptoms; endometrial thickness and histology; vaginal bleeding; breast cancer recurrence and serum lipid/lipoproteins.

RESULTS: Daily card data showed no change in the daily number of hot flushes with either tibolone or placebo (P= 0.219) after three months. There was a significant reduction in the severity of flushes with tibolone compared with placebo (-0.4 vs 0.2, P= 0.031). The Landgren scale showed a mean change in the number of hot flushes of -0.6 with tibolone and +1.1 with placebo after 12 months (P= 0.022). Endometrial biopsies were normal and vaginal bleeding was similar in both groups. A significant decrease in triglycerides (-23% vs 1.4%) and HDL (-12% vs 19%) was seen with tibolone compared with placebo after 12 months.

CONCLUSIONS: Tibolone prevented an increase in hot flushes in postmenopausal women given tamoxifen following surgery for breast cancer without untoward effects on the endometrium. Beneficial effects on serum lipid profile were noted.