Prevalence of Genetic Polymorphisms in Genes Coding for Tamoxifen Metabolising Enzymes

CYPTAM-BRUT 3 is a prospective, multicentric study in Belgium within the CYPTAM study of the Leiden University Medical Center (NTR1509) including postmenopausal women receiving tamoxifen for estrogen-receptor positive breast cancer in the adjuvant setting. The primary endpoint is the difference in uterine changes between women with a normal versus low TAS after 3 months of tamoxifen use. Secondary endpoints are serum metabolite concentrations, serum follicle-stimulating hormone level, serum sex hormone-binding globulin level and menopausal symptoms. These patients are registered in the Leiden protocol with time to breast cancer event as primary endpoint.