Andersson TML, et al. - It was determined in the current study that the change in mammographic density after a breast cancer diagnosis was associated with prognosis, as measured by cause-specific mortality, overall and with respect to hormone replacement therapy and tamoxifen treatment. A larger impact was observed of the withdrawal of hormone replacement therapy on density reduction than that of tamoxifen treatment. In contrast to previous studies, the findings revealed an association between density reduction and survival, both for tamoxifen-treated women and women who were not treated with tamoxifen.