Androgen Receptor Expression Is a Significant Prognostic Factor in Estrogen Receptor Positive Breast Cancers Treated with Chemo-Endocrine Therapy
I Castellano, E Allia, V Accortanzo, AM Vandone, L Chiusa, R Arisio, A Durando, M Donadio, G Bussolati, AS Coates, G Viale, A Sapino. University of Turin, Turin, Italy; Sant'Anna Hospital, Turin, Italy; Molinette Hospital, Turin, Italy; University of Sydney, Sydney, Australia; European Institute of Oncology, Milan, Italy
Background: Controversies remain regarding the role of androgen receptor (AR) in breast cancer patients. This study was to evaluate the prognostic value of AR expression in patients with estrogen receptor (ER) positive breast cancer treated with endocrine therapy with or without the addition of chemotherapy.
Design: A consecutive series of 953 patients with ER-positive breast cancer treated between 1998 and 2003 was selected. Repeated immunohistochemistry confirmed the expression of ER in the tumor of 938 patients. AR expression was measured by immunohistochemistry. The Kaplan-Meier method, logrank test and multivariate Cox models were used to explore the impact of AR expression on time to relapse (TTR) and disease specific survival (DSS) in all patients and in subgroups treated with chemo-endocrine therapy or endocrine therapy alone.
Results: AR immunoreactivity was assessable in 859 tumors and positive in 609 (70.9%). In the group of patients receiving chemotherapy AR positivity was a strong prognostic factor for TTR (P=.015) and DSS (P<.001). In this subset Cox models showed that AR was an independent variable for both TTR (P=.003, HR 0.444, 95%CI 0.258-0.765) and DSS (P<.001, HR 0.135, 95%CI 0.054-0.337). Finally, among the patients with tumors showing immunophenotypical features of luminal B breast cancer, AR expression identified a group of patients with better prognosis for TTR (P=.017, HR 0.521, 95%CI 0.306- 0.888) and DSS (P=.001, HR 0.276, 95% CI 0.130- 0.588).
Conclusions: AR expression is an independent prognostic factor of better outcome in patients with ER-positive breast cancers.
Wednesday, March 24, 2010 1:00 PM
Poster Session VI # 20, Wednesday Afternoon