Carcinoma of the breast during estrogen replacement therapy

Mastectomy specimens have been examined from 13 women with cancer of the breast who were taking estrogens for postmenopausal replacement therapy. The histologic types of cancer included infiltrating ductal carcinoma, medullary carcinoma, comedocarcinoma, lobular carcinoma in situ, and infiltrating lobular carcinoma. The proportions of these lesions approximated those found in large series of breast cancers unselected as to estrogen therapy. Neither specific nor bizarre epithelial alterations were recognized in the neoplasms or the nonneoplastic portions of the breast. In only one patient was it considered that the estrogens might have played a role in the induction of cancer. She was 52 years old and had taken estrogens for 32 years. The tumor was a typical infiltrating ductal carcinoma, and the remainder of the breast showed mammary duct ectasia with inactive lobules. It is concluded that neither short- nor longterm estrogen therapy produces distinctive morphological alterations nor does it alter the proportions of different histologic types of breast cancer.