Objective: To investigate the long-term effect of tibolone on mammographic density.
Design: Open-label, nonrandomized study.
Setting: Academic research environment.
Patient(s): Postmenopausal women.
Intervention(s): Tibolone was administered orally, mammograms were performed annually.
Main outcome measure(s): Mammographic density according to the Wolfe classification, performed by two independent radiologists, both of whom were blinded to treatment group.
Result(s): No statistically significant differences were found between the two groups in baseline demographic data. There were no statistically significant differences in mammographic density between the control and active groups at baseline or at 10 years.
Conclusion(s): This pilot study shows that tibolone does not adversely alter the mammographic density of the breasts over 10 years of treatment.