Abstract

PIP: Normal mammary gland cells are sensitive to a number of hormones, of which estrogen and prolactin exert the most obvious effects. Some breast cancer cells are also sensitive. Cytoplasmic receptor sites for each hormone are responsible for the interaction between the hormone and the cell. The presence of estrogen receptor has been especially studied in humans. Data collected from several sources are reviewed. The prese nce of estrogen receptors has been assayed in 154 primary breast tumors and 72 metastatic breast tumors for correlation with response to endocri ne therapy. Positive values were found in 70% of primary and 58% of metastatic specimens. Of 211 treatment trials, ablative therapy produced objective tumor regressions in 33%. Of the 94 trials with negative receptor values, only 8 were successful while 59 of the 107 trials in patients with positive receptor values succeeded. In those with borderline tumor receptor, values had a 30% response. With additive therapy, 34% of 170 trials showed tumor regression. Of these, 82 had negat ive receptor values but 8% were successful, whereas of 85 with positive receptor values, 60% were favorable. With miscellaneous therapy, 27% of 55 trials gave responses to a variety of endocrine therapies, including antiestrogens. The 32 with negative receptor values gave 16% of favorable responses whereas 43% of 23 trials in those with positive receptor values succeeded. Estrogen receptor assays performed routinely would spare patients with negative results from unnecessary major ablative therapy. Of those with positive findings, 55-60% might be benefited. The fact that all with positive receptor values do not respond is attributed to the fact that this is only part of the hormonal control system. Other biochemical lesions are assumed to have occurred in patients when endocrine therapy fails despite positive estrogen receptor levels as measured.