Serum lipids and apolipoprotein levels were measured in twenty postmenopausal women with primary breast cancer, before and three months after tamoxifen therapy (10 mg twice a day). Tamoxifen caused a significant reduction in total serum cholesterol (10%; P < 0.02), and in low-density lipoprotein cholesterol (17%; P < 0.01), and a significant 47% increase in the subclass 2 of the high density lipoprotein cholesterol (P < 0.01). In addition, tamoxifen caused a 16% increase in apolipoprotein A-I, a 12% decrease in apolipoprotein B (P < 0.05), and a 37% reduction in the serum concentration of lipoprotein(a) (P < 0.01). These results show that tamoxifen brings about an important improvement in serum lipid profile.
