PLASMA-LEVELS OF THE ATHEROGENIC AMINO-ACID HOMOCYSTEINE IN POSTMENOPAUSAL WOMEN WITH BREAST-CANCER TREATED WITH TAMOXIFEN

Long-term treatment of breast-cancer patients with the anti-oestrogen tamoxifen has been found to be associated with reduced cardiovascular mortality. Plasma homocysteine is an independent risk factor for ather osclerotic disease, and its level is determined by folate and cobalami n status, and possibly also by oestrogen status. We measured the effec t of tamoxifen on plasma homocysteine, serum cholesterol, serum cobala min and serum and erythrocyte folate in 31 post-menopausal women with breast cancer. The plasma homocysteine level was decreased by a mean v alue of 29.8% after 9-12 months and by 24.5% after 13-18 months of tre atment. Tamoxifen suppressed serum cholesterol by mean values varying between 7.2% and 17.6% after 3 to 19 months of treatment. There was no correlation between changes in plasma homocysteine and serum choleste rol, These findings suggest that the homocysteine-lowering effect of t amoxifen may contribute to the reduction of cardiovascular mortality o bserved in patients on adjuvant therapy with tamoxifen. (C) 1995 Wiley -Liss, Inc.