Assessment of results of estrogen and progesterone receptor assays performed in a community hospital

Approximately 1,000 assays for estrogen receptor (ER) in primary human breast tumors have been performed at St. Joseph's Hospital over a period of seven years; 700 of these included assays for progesterone receptor (PR). Based on the method of analysis (dextran-coated charcoal) and criteria for a positive result used for this survey, 80 percent of the primary tumors were ER-positive and 56 percent were PR-positive. In those cases where both assays were performed, 47.4 percent were ER-positive, PR-positive; 19.8 percent were ER-positive, PR-negative; 6.2 percent were ER-negative, PR-positive; and 26.6 percent were ER-negative, PR-negative. The mean concentration of ER increased with the advancing age of the patient; essentially the same relationship was observed for PR. The concentration of ER and PR was not directly dependent upon the degree of cellularity of the tumor. Lobular carcinoma and the mixed types containing ductal and lobular elements had the highest frequency of being positive for both steroid receptors, while medullary and papillary carcinomas were lowest. Three hundred and twenty-two cases had follow-up studies and were examined on the basis of the available information in the files of St. Joseph's Hospital Tumor Registry. A higher survival rate in patients with both ER and PR positivity became evident. In a community hospital setting, our data confirm the usefulness of estrogen and progesterone receptor assays in decisions of clinical management and considerations of prognosis in patients with mammary carcinoma.