<h4>Background</h4>This meta-analysis systematically evaluated the efficacy and safety of B-cell maturation antigen (BCMA)-directed chimeric antigen receptor (CAR) T-cell therapy in patients with relapsed or refractory multiple myeloma (RRMM) with extramedullary disease (EMD).<h4>Methods</h4>PubMed, Embase, Web of Science, and the Cochrane Library were searched for studies published up to December 2024 reporting CAR T-cell therapy in RRMM patients with EMD. The gene discussed is TNFRSF17; the disease is plasma cell myeloma.