Androgen Receptor in Stage I-II Primary Breast Cancer -Prognostic Value and Distribution in Subgroups.

BACKGROUND/AIM: The value of androgen receptor (AR) in breast cancer has gained renewed interest as a prognostic and treatment predictive biomarker. The aims of this work were to study the associations and the prognostic value of AR in patients from two clinical cohorts.

MATERIALS AND METHODS

Cohort 1 included 208 premenopausal, node-negative patients of whom 87% had received no adjuvant medical treatment; cohort 2 consisted of 263 patients with stage II disease who had all received 2 years of adjuvant tamoxifen. A semi-quantitative assessment of nuclear AR expression divided into five groups (0-1%, 2-10%, 11-50%, 51-75%, and 76-100%) was performed. Survival analyses, stratified by cohort, were performed using both a trend-test and a cut-off of >10% for positivity.

RESULTS

A total of 76% of all patients were AR+, and 89%, 48%, and 23% of the estrogen receptor-positive, negative, and triple-negative, respectively. In Cox regression, stratified by cohort, AR divided into five groups was a prognostic factor for 5-year distant disease-free survival with a hazard ratio of 0.86 per step in fraction score (p=0.018). With a predefined cut-off at 10%, moderate evidence of an effect remained (Hazard Ratio=0.67, p=0.077). In multivariable analysis, AR did not retain an independent prognostic value.

CONCLUSION

AR is a weak, however, not independent prognostic factor for distant metastasis. Although the prognostic value of AR may be questionable, the study identified a subset of AR-positive triple-negative patients as being potential candidates for AR-directed therapy for which further studies are warranted.