Association of 5α-reductase inhibitor prescription with immunotherapy efficacy in metastatic renal cell carcinoma: a multicenter retrospective analysis.

Background: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of metastatic renal cell carcinoma (mRCC), but response rates remain heterogeneous, and reliable predictive biomarkers are lacking. Recent studies suggest that androgen receptor (AR) signaling plays a role in regulating CD8 T-cell function, implying that 5α-reductase inhibitors (5-ARIs), which lower androgen activity, could enhance antitumor immunity and improve clinical outcomes in patients receiving immunotherapy. This study retrospectively investigates the impact of a history of 5-ARI use (≥12 months) on the efficacy of ICIs in mRCC.