Evaluation of the prognostic significance of androgen receptor expression in metastatic breast cancer.

The purpose of this study was to investigate the influence of androgen receptor (AR) expression in tumour tissue on survival of patients with metastatic breast cancer. Tumour specimens from 232 patients with metastatic breast cancer were examined for presence of AR by immunohistochemistry. According to the extent of immunostaining, AR expression was classified as score 0, 1+, 2+, or 3+. AR positivity was observed in 164 (70.7%) tumours. The median survival after disease recurrence (SAR) of patients with AR-expressing tumours was significantly longer compared to that of patients with AR-negative tumours (21.89 months, 95% CI 17.23-26.55 vs 11.99 months, 95% CI 9.36-14.62; log-rank test 0.0282). In addition, patients with AR score 3+ had a significantly longer disease-free survival (DFS) compared to patients with AR score 0, 1+, and 2+, (24.67 months, 95% CI 13.72-35.62 vs 16.36 months, 95% CI 13.18-19.54, log-rank test 0.0043). Multivariate Cox analyses showed no statistically significant influence of AR expression on DFS or SAR. In conclusion, SAR is significantly longer in patients with AR-expressing breast carcinoma. However, AR expression is not an independent prognostic factor for SAR in metastatic breast cancer.