Response to primary chemotherapy in breast cancer patients with tumors notexpressing estrogen and progesterone receptors

Background: We recently demonstrated that in premenopausal patients with es trogen receptors (ER)-absent tumors, early initiation of systemic chemother apy after primary surgery might improve outcome. These data indicate a diff erent responsiveness to chemotherapy for tumors not expressing hormone rece ptors. To test this hypothesis we evaluated the responsiveness to preoperat ive chemotherapy in patients with ER and progesterone receptors (PgR)-absen t tumors. Patients and methods: Patients with biopsy-proven T-2-T-3, N0-2 breast canc er treated at a single institution from January 1995 to August 1999 with pr eoperative chemotherapy were retrospectively evaluated. ER and PgR were det ermined immunohistochemically and classified for this purpose as absent (0% of the cells positive) or positive (greater than or equal to 1% of the cel ls). Results: On 117 evaluable patients 72 had an objective response (61%). A si gnificant difference in response was observed for patients with ER and PgR absent compared with those with ER and/or PgR-positive tumors (82% vs. 57%, P = 0.03 Fishers's exact test). Pathological complete remission rates were also significantly different in the two groups (23% vs. 7%, respectively; P = 0.04). Conclusions: The different degree of response according to hormone receptor s expression supports the hypothesis that tumors not expressing both ER and PgR might represent a different clinical entity in terms of chemotherapy r esponsiveness.