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 tamoxi fen in breast cancer patients who had undergone surgery. MATERIALS AND METHODS. We reviewed the mammograms of 102 breast cancer pati ents treated with tamoxifen (20 mg per day); these patients were subgrouped into tamoxifen-only patients and patients treated with tamoxifen in combin ation with another therapy (chemotherapy, radiotherapy, or both). The contr ol group was made up of 50 breast cancer patients who did not undergo tamox ifen therapy and 20 healthy women who had an age distribution and menstruat ion status similar to those of the breast cancer patients. Two radiologists evaluated parenchymal patterns on mammograms of the contralateral breast i n the breast cancer patients and of the left breast in the healthy women. P arenchymal 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 pare nchyma was shown to be decreased after tamoxifen therapy. Mammography can b e a useful method for evaluating breast parenchymal changes after tamoxifen treatment.