A retrospective study of 40 Chinese patients found that extramedullary relapse after BCMA-directed CAR-T therapy correlates with significantly inferior survival and weaker responses to salvage treatment. The findings connect disease distribution at relapse to downstream outcomes after cellular therapy. For clinicians, the study highlights a subgroup signal that may affect risk stratification after CAR-T and informs post-therapy monitoring strategy in myeloma patients at risk of disease spread beyond marrow.