Association between steroid hormone receptors and response rate to cytotoxic chemotherapy in metastatic breast cancer.

The influence of steroid hormone receptors on response rate to cytotoxic chemotherapy in 70 patients with metastatic breast cancer was determined in a retrospective study. We have previously reported that 34 of 45 patients with tumors containing low or absent estrogen-receptor values had objective responses to chemotherapy while three of 25 patients with positive estrogen-receptor tumors responded. In the present study, 22 of 34 patients with low or absent progesterone-receptor tumors had an objective response to cytotoxic chemotherapy, while none of eight patients with a positive progesterone-receptor tumor responded (P less than 0.05). Patients having tumors with a negative estrogen receptor and a negative progesterone receptor had a response rate of 88% (21 of 24 patients). There were three patients whose tumors were estrogen-receptor negative but progesterone-receptor positive; none had a response to chemotherapy. Chemotherapy response was not associated with the presence or absence of either androgen or glucocorticoid receptor. We conclude that progesterone-receptor values in addition to estrogen-receptor status may prove to be important correlates of response to cytotoxic chemotherapy in metastatic breast cancer. Androgen- and glucocorticoid-receptor analyses are not helpful in predicting response to chemotherapy.