THE EFFECTS OF TAMOXIFEN ON THE ENDOMETRIUM, BLOOD-FLOW OF THE UTERINE ARTERIES AND SERUM-LIPOPROTEIN (A) LEVELS IN POSTMENOPAUSAL WOMEN

The purpose of this study was to evaluate the effect of tamoxifen ther apy on the endometrium by transvaginal color Doppler sonography and on lipid profile focusing on lipoprotein (a) [Lp(a)] levels. Seventy-fiv e postmenopausal breast cancer patients were examined by transvaginal color Doppler sonography and serum Lp(a) levels. Lipid parameters were measured after overnight fasting. Forty of the patients were treated with tamoxifen (20-30 mg/day) for at least 1 year. The remaining 35 pa tients did not receive tamoxifen and were used as controls. Statistica l analysis was performed using t-test and Mann-Whitney U-test (Systat version 5.0). The patients receiving tamoxifen had significantly thick er endometrium (7.9 +/- 3.6 mm) compared to the control group (4.5 +/- 1.8 mm) (p less than or equal to 0.001). The mean pulsatility index a nd resistance index of the uterine arteries in the tamoxifen group wer e 2.063 +/- 0.49 and 0.83 +/- 0.07, respectively, and were significant ly lower than those of the control group (2.69 +/- 0.16 and 0.88 +/- 0 .02) (p < 0.001). In addition, tamoxifen decreased total cholesterol ( p < 0.001) and low-density lipoprotein cholesterol (p < 0.001) and apo lipoprotein B (p < 0.05) significantly. Tamoxifen also increased high- density lipoprotein cholesterol (p < 0.05) and apolipoprotein A-I (p < 0.05). These results indicate that tamoxifen stimulates the endometri um and acts as an anti-atherogenic agent in postmenopausal women.