Impact of androgen receptor on triple negative breast cancer: a systematic review and meta-analytic study

Objectives: To evaluate the prognostic impact of androgen receptor (AR) protein expression on disease-free survival (DFS) and overall survival (OS) in patients with triple-negative breast cancer (TNBC). Design: Systematic review and meta-analysis. Data sources: Cochrane Library, MEDLINE, Embase, Google Scholar and Web of Science (1 January 2000-30 November 2024). Eligibility criteria: Studies assessing AR protein expression in tumour tissue from female TNBC patients using immunohistochemistry and reporting multivariable HRs with 95% CIs for DFS and/or OS were eligible. Data extraction and synthesis: Screening, data extraction and risk-of-bias assessment were performed independently and in duplicate. Random-effects meta-analyses were conducted using the DerSimonian-Laird method with Hartung-Knapp-Sidik-Jonkman adjustment. Subgroup, meta-regression and leave-one-out sensitivity analyses explored heterogeneity. Publication bias was assessed with funnel plots and Egger's test. Study quality was appraised using the Cochrane Risk of Bias 2 tool. Results: 11 studies involving 4446 patients were included; AR was expressed in 1261 (28.4%). AR positivity showed a non-significant trend towards improved DFS (HR 0.67, 95% CI 0.44 to 1.03; p=0.07) and OS (HR 0.76, 95% CI 0.49 to 1.18; p=0.20). Subgroup analyses demonstrated significant DFS benefits in studies with ≤5 years' follow-up (HR 0.81, 95% CI 0.60 to 1.10; p=0.03) and in upper-middle-income countries (HR 0.45, 95% CI 0.24 to 0.83; p=0.01). Meta-regression identified AR cut-off (≥5%) as a significant moderator (HR 0.33, 95% CI 0.27 to 0.41; p