Background: Contradictory reports regarding the role of the androgen receptor (AR) in breast cancer (BC).The current study aimed to evaluate the prognostic and predictive value of AR expression in postmenopausal luminal BC and response to tamoxifen (TAM) versus aromatase inhibitors (AIs).

Methods: A retrospective study included postmenopausal female patients with luminal BC treated with TAM or AI from February 2015 to December 2020.

Results:

Eighty percent of the patients had AR expression. Low grade, small tumor size, less involvement of lymph nodes, hormone receptor positive, low ki67, and her-2-ve were associated with AR +ve (p 0.001). Compared to 21.4% and 23.2% of AR-ve patients, only 16.2% of AR+ve patients experienced relapses and 10.5% died. The OS improvement for AR+ve patients was statistically significant (79.3 vs. 82.0 p 0.014), but the difference in DFS between AR-ve and AR+ve patients was not significant (74.5 vs. 75.6 p 0.11). In AR-ve patients, there was no significant difference between the TAM and AI groups in terms of DFS or OS (73.4 vs. 74.2, p 0.9; 78.2 vs. 78.9, p 0.84, respectively), but AR+ve patients, there was a statistically significant difference in DFS and a trend toward improved OS (71.2 vs. 77.7, p 0.04; 78.7 vs. 83.7, p 0.06, respectively)

Conclusion:

AR expression is associated with favorable pathological characteristics and a better survival outcome. Although our results showed improvement in DFS in patients who received AI in adjuvant settings, we still need more data to consider AR as a routine predictive marker in this scenario.