Long-term estrogen replacement therapy (ERT) offers many benefits to menopausal women, including relief from menopausal symptoms and protection from coronary artery disease and osteoporosis. ERT has also been linked to an increased risk for endometrial and breast cancer. However, ERT has been shown to be a reasonable treatment for menopausal women, provided they are properly informed about these risks. Little is known about the relationship between ERT and the risk for breast cancer in women with benign breast disease. Dupont and associates conducted a retrospective study of women with benign breast disease established by biopsy to identify a possible link between ERT and breast cancer risk.

Medical records from 1952 to 1978 of women whose biopsy results indicated benign breast parenchyma or fibroadenoma were reviewed for the study. Patients who met the inclusion criteria, or their next of kin, were subsequently interviewed to identify a history of any breast cancer, use of ERT and other breast cancer risks. All reported cases of breast cancer were confirmed by a review of the patient's histology slides or medical records.

A total of 9,494 women met the inclusion criteria and, of these, 444 had confirmed breast cancer. The risk for breast cancer was significantly higher in patients whose initial biopsy results showed atypical hyperplasia, proliferative disease without atypia or complex fibroadenoma. However, the use of ERT and the duration of therapy were not associated with an increased risk for breast cancer.

The authors conclude that the use of ERT and the duration of therapy do not increase the risk for breast cancer in women with benign breast disease. Rather, ERT offers multiple benefits to postmenopausal women. Therefore, ERT should not be contraindicated in women with benign breast disease.