Significance of follow-up mammography in estimating the effect of tamoxifen in breast cancer patients who have undergone surgery.

OBJECTIVE: We evaluated mammographic changes to assess the effect of tamoxifen in breast cancer patients who had undergone surgery. MATERIALS AND METHODS: We reviewed the mammograms of 102 breast cancer patients treated with tamoxifen (20 mg per day); these patients were subgrouped into tamoxifen-only patients and patients treated with tamoxifen in combination with another therapy (chemotherapy, radiotherapy, or both). The control group was made up of 50 breast cancer patients who did not undergo tamoxifen therapy and 20 healthy women who had an age distribution and menstruation status similar to those of the breast cancer patients. Two radiologists evaluated parenchymal patterns on mammograms of the contralateral breast in the breast cancer patients and of the left breast in the healthy women. Parenchymal changes before and after surgery were also analyzed. RESULTS: Follow-up mammography showed decreased breast parenchyma in 59.8% of the tamoxifen group, 87.0% of the premenopausal tamoxifen-treated women, 36.0% of the nontamoxifen patients, and 10.0% of the healthy women. CONCLUSION: On follow-up mammography of breast cancer patients, breast parenchyma was shown to be decreased after tamoxifen therapy. Mammography can be a useful method for evaluating breast parenchymal changes after tamoxifen treatment.