Do estrogen and progesterone receptors (E2R and PR) in metastasizing endometrial cancers predict the response to gestagen therapy?

In a prospective investigation biopsy specimens were obtained of 150 women with primary, untreated endometrial carcinoma for determinination of the content of estrogen and progesterone receptors (E2 and PR). After a varying interval 13 who developed metastases despite routine surgical and radiation therapy received treatment with gestagens. The clinical effect of the hormone was studied for any correlation with the initial content of E2 and PR. Eight of the women (61--71 years) proved E2R positive (greater than 10 fmoles/mg cytosolprotein), 2 had no PR and the remaining 6 had PR in a concentration of 7--892 fmoles/mg cytosolprotein). 7 responded clinically to gestagen therapy (tumors poorly differentiated in 3 and moderately in 4). Five of the women (50--84 years) were E2R negative; they had no PR, they did not respond to gestagen therapy and died after 2--8 months (tumors poorly differentiated in 2 and moderatley in 3). Determination of E2R and PR in endometrial carcinoma appears to be a clinically useful test for predicting whether a patient is likely to respond to treatment with gestagens.