Objective: One of the most important factors contributing to developing of the breast cancer is a female organism exposure to estrogens. Thickness and structure of endometrium in postmenopausal women is a sign of the hormonal status. The goal of the study was to investigate whether there is a difference in the endometrial thickness and quality in postmenopausal women with breast cancer. Design: Prospective cohort study. Setting: Ultrasound Unit, 2nd Department of Obstetrics and Gynecology, Medical School and Medical Teaching Hospital of L. Pasteur, Košice, Slovakia. Material and Methods: Endometrial thickness was measured by transvaginal ultrasonography in 21 patients with histologically verified breast cancer and was compared with a group of 26 well women. We assessed the thickness of endometrium, the size of uterus and the endometrium/myometrium index. Results: Despite the fact there existed a difference between these two groups (the average thickness of 3.6 mm and 2.9 mm), the result was not statistically applicable to show a correlation with a benign or malignant breast tissue. Conclusion: The results may support the theory of breast cancerogenesis in correlation with estrogen influence or increased incidence of estrogen receptors, respectively. As definitive statistical result can not be stated due to a limited group of patients, more investigation might be necessary in the future. The study dealing with a similar problem was not found in available publications.

        Key words: endometrium, breast cancer, ultrasonography