Influence of aromatase inhibitors on plasma total homocysteine in postmenopausal breast cancer patients

In this study, we evaluated the effect of estrogen suppression with three a romatase inhibitors, aminoglutethimide (n = 30), formestane (n = 12), and e xemestane (n = 10), and the progestin megestrol acetate (n = 21) on plasma total homocysteine (tHcy) in patients suffering from advanced breast cancer . Treatment with 1 g/day aminoglutethimide for 2 and 3-5 months increased p lasma tHcy by a mean value of 24.5% [95% confidence interval, 10.5-40.4%] a t 2 months and 35.8% (95% confidence interval, 18.2-55.9%) at 3-5 months, c orresponding to increases in the mean plasma tHcy of 1.90 and 3.67 mu mol/L , respectively. In contrast, none of the other treatment options influenced plasma tHcy concentrations. The finding that aminoglutethimide, but none o f the other aromatase inhibitors or megestrol acetate, influenced plasma tH cy suggests that this effect is achieved by mechanisms not related to suppr ession of plasma estrogens or to the glucocorticoids administered in concer t.