This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bartsch, R. Articles by Steger, G. G. Search for Related Content PubMed PubMed Citation Articles by Bartsch, R. Articles by Steger, G. G.

Her2 and Progesterone Receptor Status Are Not Predictive of Response to Fulvestrant Treatment

Authors' Affiliations: ¹ First Department of Medicine and Cancer Centre, Clinical Division of Oncology, ² Department of Surgery, and ³ Department of Pathology, Medical University of Vienna, Vienna, Austria

Requests for reprints: Guenther G. Steger, First Department of Medicine and Cancer Centre, Clinical Division of Oncology, Medical University of Vienna, 18-20 Waehringer Guertel, A-1090 Vienna, Austria. Phone: 43-1-40400-4426; Fax: 43-1-40400-6081; E-mail: guenther.steger{at}meduniwien.ac.at.

Purpose: It has been hypothesized that response to endocrine therapy for breast cancer depends on Her2 and progesterone receptor status, grading, and tumor proliferation rate. In this study, we evaluated factors that are potentially predictive of response and time to progression in patients treated with fulvestrant.

Experimental Design: One hundred fifty-five patients were included and followed prospectively. Patients received fulvestrant at standard dose by i.m. injection. Response was evaluated every 3 months using International Union Against Cancer criteria. Time to progression and overall survival were estimated with the Kaplan-Meier product limit method. A multivariate analysis was done to evaluate factors potentially influencing response and time to progression.

Results: We observed a partial response in 19 patients (12.3%), stable disease 6 months in 56 patients (36.1%), stable disease >3 months but <6 months in 7 patients (4.5%), and progressive disease in 73 patients (47.1%). Median time to progression was 5 months, and median overall survival was 27 months. Probability of achieving clinical benefit was significantly associated with a low proliferation rate (P = 0.015), nonvisceral metastatic sites (P = 0.023), and first-line therapy (P = 0.023). First-line therapy was also associated with prolonged time to progression (P = 0.003).

Conclusions: Response rate and time to progression are shown to be independent of Her2 status, grading, and progesterone receptor status. This is probably caused by the unique mechanism of action associated with fulvestrant: Due to receptor down-regulation, it blocks nuclear, cytoplasmatic, and membrane-bound estrogen receptor. Therefore, it seems to inhibit the cross-talk between growth factor receptor signaling and estrogen receptor in a more effective manner.

This article has been cited by other articles:

				J. S. Ross, E. A. Slodkowska, W. F. Symmans, L. Pusztai, P. M. Ravdin, and G. N. Hortobagyi The HER-2 Receptor and Breast Cancer: Ten Years of Targeted Anti-HER-2 Therapy and Personalized Medicine Oncologist, April 1, 2009; 14(4): 320 - 368. [Abstract] [Full Text] [PDF]