A retrospective study of 109 patients found that CD19-directed CAR T-cell therapy shrank lymphoma tumors across both nodal and extranodal sites, but survival still varied sharply by disease location. The results separate tumor shrinkage from durable outcomes, implying that anatomical site and microenvironment could influence persistence. For CAR T developers and trial designers, the study highlights the importance of incorporating disease site as a stratification factor when interpreting efficacy and planning follow-up. Clinically, it supports more nuanced patient counseling and risk assessment beyond response rates alone.