Serum homocysteine levels in postmenopausal breast cancer patients treated with tamoxifen

Adjuvant treatment of breast cancer with tamoxifen may be associated with reduced risk of cardiovascular disease. Serum homocysteine level has been suggested to be a risk factor for cardiovascular disease influenced by estrogenic hormones. We evaluated a subset of postmenopausal women who had participated in a longitudinal, double-blind, randomized, placebo-controlled toxicity study of tamoxifen 10 mg orally, twice daily. Twenty-seven treated subjects and 37 placebo subjects had measurements of serum homocysteine levels made on previously frozen samples obtained at baseline and after 12 months. After treatment with tamoxifen, we found lower levels of serum homocysteine of borderline statistical significance.