Mammographic changes after hormone replacement therapy in patients who have undergone breast irradiation.

Objective: We examined three patients who began hormone replacement therapy after lumpectomy and breast irradiation. In these women increased tissue density appeared on mammography only or disproportionately in the nonirradiated breast. To our knowledge, this observation has not been reported.

Conclusion: Breast irradiation may induce tissue changes that prevent or diminish the proliferative response that can be induced in breast tissue by postmenopausal hormone replacement therapy. Because this treatment is now recommended for some women after breast conservation therapy, mammographers may recognize this finding with increasing frequency.