Estrogen receptor status and response to polychemotherapy in advanced breast cancer

In a retrospective study, response to systemic polychemotherapy was analyzed in 72 female patients having advanced breast cancer and correlated with estrogen receptor (ER) status. Estrogen receptors were analyzed by agar-gel electrophoresis or uptake competition technique in tumor biopsy specimens derived from the primary tumor or from metastases. The borderline between positive and negative ER values was declared to be 20 fmol/mg tissue protein. Most of the patients have had an extramural review. We did not find statistically significant differences between the ER-positive (ER+), and ER-negative (ER-) groups in these characteristics: age; menopausal status; disease-free interval; dominant site of involvement. Chemotherapy regimens utilized in the two groups were comparable. According to criteria formulated by the European Organization on Research and Treatment of Cancer (EORTC), there is no evidence that response to chemotherapy is correlated with the presence or absence of estrogen receptor. Thirteen of 31 ER+ patients responded objectively to chemotherapy (42%) and 17 or 41 ER- patients gained such remission (41%). Given the retrospective nature of the data, this result should be interpreted cautiously. More clinical studies are warranted to determine whether response to cytotoxic agents is affected by ER status.