Estrogen receptor status in breast cancer.

This very brief discussion of the prognostic and diagnostic role of hormone receptors in breast tumors attempts to put into perspective the usefulness of hormone manipulation in treatment of breast cancer. About 60% of breast tumors contain estrogen receptors (ER+); about 75% of breast tumors contain positive progesterone receptors (PR+). Positivity for ER+ is usually considered if estrogen uptake in the receptor assay exceeds 9 fmol per mg of protein, but it is pointed out that some tumors may take up 100 fmol, so the positivity of breast tumors has wide variety. Hormone therapy has been found effective in 60% of ER+ tumors vs. 5% in ER- tumors; when both ER+ and PR+ are present, success rate of hormone therapy increases to 75%; however, this author cautions that by "success" disease eradication is not meant; rather it indicates some degree of tumor regression or perhaps merely alleviation of symptoms. In terms of hormonal management of a patient with metastatic breast cancer, the following schedule, based on a consensus, is offered: ER+ patients who are premenopausal or within 5 years of menopause should undergo ovariectomy; postmenopausal patients should be treated with estrogens or tamoxifen in sequence; adrenalectomy might be considered in the occasional patient with severe metastatic bone pain resistant to estrogens and tamoxifen and unsuitable for localized radiotherapy. Hypophysectomy is never indicated. Biopsy material for ER assay should be the first specimen; a 1-gm quantity is needed; and this author uses the dextran-coated ER assay.